FreeBSD/Linux Kernel Cross Reference
sys/kern/uipc_ktls.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause
      *
      * Copyright (c) 2014-2019 Netflix Inc.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include "opt_inet.h"
    #include "opt_inet6.h"
    #include "opt_kern_tls.h"
    #include "opt_ratelimit.h"
    #include "opt_rss.h"
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/domainset.h>
    #include <sys/endian.h>
    #include <sys/ktls.h>
    #include <sys/lock.h>
    #include <sys/mbuf.h>
    #include <sys/mutex.h>
    #include <sys/rmlock.h>
    #include <sys/proc.h>
    #include <sys/protosw.h>
    #include <sys/refcount.h>
    #include <sys/smp.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/sysctl.h>
    #include <sys/taskqueue.h>
    #include <sys/kthread.h>
    #include <sys/uio.h>
    #include <sys/vmmeter.h>
    #if defined(__aarch64__) || defined(__amd64__) || defined(__i386__)
    #include <machine/pcb.h>
    #endif
    #include <machine/vmparam.h>
    #include <net/if.h>
    #include <net/if_var.h>
    #ifdef RSS
    #include <net/netisr.h>
    #include <net/rss_config.h>
    #endif
    #include <net/route.h>
    #include <net/route/nhop.h>
    #if defined(INET) || defined(INET6)
    #include <netinet/in.h>
    #include <netinet/in_pcb.h>
    #endif
    #include <netinet/tcp_var.h>
    #ifdef TCP_OFFLOAD
    #include <netinet/tcp_offload.h>
    #endif
    #include <opencrypto/cryptodev.h>
    #include <opencrypto/ktls.h>
    #include <vm/uma_dbg.h>
    #include <vm/vm.h>
    #include <vm/vm_pageout.h>
    #include <vm/vm_page.h>
    #include <vm/vm_pagequeue.h>
    
    struct ktls_wq {
            struct mtx      mtx;
            STAILQ_HEAD(, mbuf) m_head;
            STAILQ_HEAD(, socket) so_head;
            bool            running;
            int             lastallocfail;
    } __aligned(CACHE_LINE_SIZE);
    
    struct ktls_alloc_thread {
            uint64_t wakeups;
            uint64_t allocs;
            struct thread *td;
            int running;
    };
    
   struct ktls_domain_info {
           int count;
           int cpu[MAXCPU];
           struct ktls_alloc_thread alloc_td;
   };
   
   struct ktls_domain_info ktls_domains[MAXMEMDOM];
   static struct ktls_wq *ktls_wq;
   static struct proc *ktls_proc;
   static uma_zone_t ktls_session_zone;
   static uma_zone_t ktls_buffer_zone;
   static uint16_t ktls_cpuid_lookup[MAXCPU];
   static int ktls_init_state;
   static struct sx ktls_init_lock;
   SX_SYSINIT(ktls_init_lock, &ktls_init_lock, "ktls init");
   
   SYSCTL_NODE(_kern_ipc, OID_AUTO, tls, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
       "Kernel TLS offload");
   SYSCTL_NODE(_kern_ipc_tls, OID_AUTO, stats, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
       "Kernel TLS offload stats");
   
   #ifdef RSS
   static int ktls_bind_threads = 1;
   #else
   static int ktls_bind_threads;
   #endif
   SYSCTL_INT(_kern_ipc_tls, OID_AUTO, bind_threads, CTLFLAG_RDTUN,
       &ktls_bind_threads, 0,
       "Bind crypto threads to cores (1) or cores and domains (2) at boot");
   
   static u_int ktls_maxlen = 16384;
   SYSCTL_UINT(_kern_ipc_tls, OID_AUTO, maxlen, CTLFLAG_RDTUN,
       &ktls_maxlen, 0, "Maximum TLS record size");
   
   static int ktls_number_threads;
   SYSCTL_INT(_kern_ipc_tls_stats, OID_AUTO, threads, CTLFLAG_RD,
       &ktls_number_threads, 0,
       "Number of TLS threads in thread-pool");
   
   unsigned int ktls_ifnet_max_rexmit_pct = 2;
   SYSCTL_UINT(_kern_ipc_tls, OID_AUTO, ifnet_max_rexmit_pct, CTLFLAG_RWTUN,
       &ktls_ifnet_max_rexmit_pct, 2,
       "Max percent bytes retransmitted before ifnet TLS is disabled");
   
   static bool ktls_offload_enable;
   SYSCTL_BOOL(_kern_ipc_tls, OID_AUTO, enable, CTLFLAG_RWTUN,
       &ktls_offload_enable, 0,
       "Enable support for kernel TLS offload");
   
   static bool ktls_cbc_enable = true;
   SYSCTL_BOOL(_kern_ipc_tls, OID_AUTO, cbc_enable, CTLFLAG_RWTUN,
       &ktls_cbc_enable, 1,
       "Enable support of AES-CBC crypto for kernel TLS");
   
   static bool ktls_sw_buffer_cache = true;
   SYSCTL_BOOL(_kern_ipc_tls, OID_AUTO, sw_buffer_cache, CTLFLAG_RDTUN,
       &ktls_sw_buffer_cache, 1,
       "Enable caching of output buffers for SW encryption");
   
   static int ktls_max_alloc = 128;
   SYSCTL_INT(_kern_ipc_tls, OID_AUTO, max_alloc, CTLFLAG_RWTUN,
       &ktls_max_alloc, 128,
       "Max number of 16k buffers to allocate in thread context");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_tasks_active);
   SYSCTL_COUNTER_U64(_kern_ipc_tls, OID_AUTO, tasks_active, CTLFLAG_RD,
       &ktls_tasks_active, "Number of active tasks");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_cnt_tx_pending);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, sw_tx_pending, CTLFLAG_RD,
       &ktls_cnt_tx_pending,
       "Number of TLS 1.0 records waiting for earlier TLS records");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_cnt_tx_queued);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, sw_tx_inqueue, CTLFLAG_RD,
       &ktls_cnt_tx_queued,
       "Number of TLS records in queue to tasks for SW encryption");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_cnt_rx_queued);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, sw_rx_inqueue, CTLFLAG_RD,
       &ktls_cnt_rx_queued,
       "Number of TLS sockets in queue to tasks for SW decryption");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_offload_total);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, offload_total,
       CTLFLAG_RD, &ktls_offload_total,
       "Total successful TLS setups (parameters set)");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_offload_enable_calls);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, enable_calls,
       CTLFLAG_RD, &ktls_offload_enable_calls,
       "Total number of TLS enable calls made");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_offload_active);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, active, CTLFLAG_RD,
       &ktls_offload_active, "Total Active TLS sessions");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_offload_corrupted_records);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, corrupted_records, CTLFLAG_RD,
       &ktls_offload_corrupted_records, "Total corrupted TLS records received");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_offload_failed_crypto);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, failed_crypto, CTLFLAG_RD,
       &ktls_offload_failed_crypto, "Total TLS crypto failures");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_switch_to_ifnet);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, switch_to_ifnet, CTLFLAG_RD,
       &ktls_switch_to_ifnet, "TLS sessions switched from SW to ifnet");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_switch_to_sw);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, switch_to_sw, CTLFLAG_RD,
       &ktls_switch_to_sw, "TLS sessions switched from ifnet to SW");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_switch_failed);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, switch_failed, CTLFLAG_RD,
       &ktls_switch_failed, "TLS sessions unable to switch between SW and ifnet");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_ifnet_disable_fail);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, ifnet_disable_failed, CTLFLAG_RD,
       &ktls_ifnet_disable_fail, "TLS sessions unable to switch to SW from ifnet");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_ifnet_disable_ok);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_stats, OID_AUTO, ifnet_disable_ok, CTLFLAG_RD,
       &ktls_ifnet_disable_ok, "TLS sessions able to switch to SW from ifnet");
   
   SYSCTL_NODE(_kern_ipc_tls, OID_AUTO, sw, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
       "Software TLS session stats");
   SYSCTL_NODE(_kern_ipc_tls, OID_AUTO, ifnet, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
       "Hardware (ifnet) TLS session stats");
   #ifdef TCP_OFFLOAD
   SYSCTL_NODE(_kern_ipc_tls, OID_AUTO, toe, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
       "TOE TLS session stats");
   #endif
   
   static COUNTER_U64_DEFINE_EARLY(ktls_sw_cbc);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_sw, OID_AUTO, cbc, CTLFLAG_RD, &ktls_sw_cbc,
       "Active number of software TLS sessions using AES-CBC");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_sw_gcm);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_sw, OID_AUTO, gcm, CTLFLAG_RD, &ktls_sw_gcm,
       "Active number of software TLS sessions using AES-GCM");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_sw_chacha20);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_sw, OID_AUTO, chacha20, CTLFLAG_RD,
       &ktls_sw_chacha20,
       "Active number of software TLS sessions using Chacha20-Poly1305");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_ifnet_cbc);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_ifnet, OID_AUTO, cbc, CTLFLAG_RD,
       &ktls_ifnet_cbc,
       "Active number of ifnet TLS sessions using AES-CBC");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_ifnet_gcm);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_ifnet, OID_AUTO, gcm, CTLFLAG_RD,
       &ktls_ifnet_gcm,
       "Active number of ifnet TLS sessions using AES-GCM");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_ifnet_chacha20);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_ifnet, OID_AUTO, chacha20, CTLFLAG_RD,
       &ktls_ifnet_chacha20,
       "Active number of ifnet TLS sessions using Chacha20-Poly1305");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_ifnet_reset);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_ifnet, OID_AUTO, reset, CTLFLAG_RD,
       &ktls_ifnet_reset, "TLS sessions updated to a new ifnet send tag");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_ifnet_reset_dropped);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_ifnet, OID_AUTO, reset_dropped, CTLFLAG_RD,
       &ktls_ifnet_reset_dropped,
       "TLS sessions dropped after failing to update ifnet send tag");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_ifnet_reset_failed);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_ifnet, OID_AUTO, reset_failed, CTLFLAG_RD,
       &ktls_ifnet_reset_failed,
       "TLS sessions that failed to allocate a new ifnet send tag");
   
   static int ktls_ifnet_permitted;
   SYSCTL_UINT(_kern_ipc_tls_ifnet, OID_AUTO, permitted, CTLFLAG_RWTUN,
       &ktls_ifnet_permitted, 1,
       "Whether to permit hardware (ifnet) TLS sessions");
   
   #ifdef TCP_OFFLOAD
   static COUNTER_U64_DEFINE_EARLY(ktls_toe_cbc);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_toe, OID_AUTO, cbc, CTLFLAG_RD,
       &ktls_toe_cbc,
       "Active number of TOE TLS sessions using AES-CBC");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_toe_gcm);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_toe, OID_AUTO, gcm, CTLFLAG_RD,
       &ktls_toe_gcm,
       "Active number of TOE TLS sessions using AES-GCM");
   
   static COUNTER_U64_DEFINE_EARLY(ktls_toe_chacha20);
   SYSCTL_COUNTER_U64(_kern_ipc_tls_toe, OID_AUTO, chacha20, CTLFLAG_RD,
       &ktls_toe_chacha20,
       "Active number of TOE TLS sessions using Chacha20-Poly1305");
   #endif
   
   static MALLOC_DEFINE(M_KTLS, "ktls", "Kernel TLS");
   
   #if defined(INET) || defined(INET6)
   static void ktls_reset_receive_tag(void *context, int pending);
   static void ktls_reset_send_tag(void *context, int pending);
   #endif
   static void ktls_work_thread(void *ctx);
   static void ktls_alloc_thread(void *ctx);
   
   #if defined(INET) || defined(INET6)
   static u_int
   ktls_get_cpu(struct socket *so)
   {
           struct inpcb *inp;
   #ifdef NUMA
           struct ktls_domain_info *di;
   #endif
           u_int cpuid;
   
           inp = sotoinpcb(so);
   #ifdef RSS
           cpuid = rss_hash2cpuid(inp->inp_flowid, inp->inp_flowtype);
           if (cpuid != NETISR_CPUID_NONE)
                   return (cpuid);
   #endif
           /*
            * Just use the flowid to shard connections in a repeatable
            * fashion.  Note that TLS 1.0 sessions rely on the
            * serialization provided by having the same connection use
            * the same queue.
            */
   #ifdef NUMA
           if (ktls_bind_threads > 1 && inp->inp_numa_domain != M_NODOM) {
                   di = &ktls_domains[inp->inp_numa_domain];
                   cpuid = di->cpu[inp->inp_flowid % di->count];
           } else
   #endif
                   cpuid = ktls_cpuid_lookup[inp->inp_flowid % ktls_number_threads];
           return (cpuid);
   }
   #endif
   
   static int
   ktls_buffer_import(void *arg, void **store, int count, int domain, int flags)
   {
           vm_page_t m;
           int i, req;
   
           KASSERT((ktls_maxlen & PAGE_MASK) == 0,
               ("%s: ktls max length %d is not page size-aligned",
               __func__, ktls_maxlen));
   
           req = VM_ALLOC_WIRED | VM_ALLOC_NODUMP | malloc2vm_flags(flags);
           for (i = 0; i < count; i++) {
                   m = vm_page_alloc_noobj_contig_domain(domain, req,
                       atop(ktls_maxlen), 0, ~0ul, PAGE_SIZE, 0,
                       VM_MEMATTR_DEFAULT);
                   if (m == NULL)
                           break;
                   store[i] = (void *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m));
           }
           return (i);
   }
   
   static void
   ktls_buffer_release(void *arg __unused, void **store, int count)
   {
           vm_page_t m;
           int i, j;
   
           for (i = 0; i < count; i++) {
                   m = PHYS_TO_VM_PAGE(DMAP_TO_PHYS((vm_offset_t)store[i]));
                   for (j = 0; j < atop(ktls_maxlen); j++) {
                           (void)vm_page_unwire_noq(m + j);
                           vm_page_free(m + j);
                   }
           }
   }
   
   static void
   ktls_free_mext_contig(struct mbuf *m)
   {
           M_ASSERTEXTPG(m);
           uma_zfree(ktls_buffer_zone, (void *)PHYS_TO_DMAP(m->m_epg_pa[0]));
   }
   
   static int
   ktls_init(void)
   {
           struct thread *td;
           struct pcpu *pc;
           int count, domain, error, i;
   
           ktls_wq = malloc(sizeof(*ktls_wq) * (mp_maxid + 1), M_KTLS,
               M_WAITOK | M_ZERO);
   
           ktls_session_zone = uma_zcreate("ktls_session",
               sizeof(struct ktls_session),
               NULL, NULL, NULL, NULL,
               UMA_ALIGN_CACHE, 0);
   
           if (ktls_sw_buffer_cache) {
                   ktls_buffer_zone = uma_zcache_create("ktls_buffers",
                       roundup2(ktls_maxlen, PAGE_SIZE), NULL, NULL, NULL, NULL,
                       ktls_buffer_import, ktls_buffer_release, NULL,
                       UMA_ZONE_FIRSTTOUCH);
           }
   
           /*
            * Initialize the workqueues to run the TLS work.  We create a
            * work queue for each CPU.
            */
           CPU_FOREACH(i) {
                   STAILQ_INIT(&ktls_wq[i].m_head);
                   STAILQ_INIT(&ktls_wq[i].so_head);
                   mtx_init(&ktls_wq[i].mtx, "ktls work queue", NULL, MTX_DEF);
                   if (ktls_bind_threads > 1) {
                           pc = pcpu_find(i);
                           domain = pc->pc_domain;
                           count = ktls_domains[domain].count;
                           ktls_domains[domain].cpu[count] = i;
                           ktls_domains[domain].count++;
                   }
                   ktls_cpuid_lookup[ktls_number_threads] = i;
                   ktls_number_threads++;
           }
   
           /*
            * If we somehow have an empty domain, fall back to choosing
            * among all KTLS threads.
            */
           if (ktls_bind_threads > 1) {
                   for (i = 0; i < vm_ndomains; i++) {
                           if (ktls_domains[i].count == 0) {
                                   ktls_bind_threads = 1;
                                   break;
                           }
                   }
           }
   
           /* Start kthreads for each workqueue. */
           CPU_FOREACH(i) {
                   error = kproc_kthread_add(ktls_work_thread, &ktls_wq[i],
                       &ktls_proc, &td, 0, 0, "KTLS", "thr_%d", i);
                   if (error) {
                           printf("Can't add KTLS thread %d error %d\n", i, error);
                           return (error);
                   }
           }
   
           /*
            * Start an allocation thread per-domain to perform blocking allocations
            * of 16k physically contiguous TLS crypto destination buffers.
            */
           if (ktls_sw_buffer_cache) {
                   for (domain = 0; domain < vm_ndomains; domain++) {
                           if (VM_DOMAIN_EMPTY(domain))
                                   continue;
                           if (CPU_EMPTY(&cpuset_domain[domain]))
                                   continue;
                           error = kproc_kthread_add(ktls_alloc_thread,
                               &ktls_domains[domain], &ktls_proc,
                               &ktls_domains[domain].alloc_td.td,
                               0, 0, "KTLS", "alloc_%d", domain);
                           if (error) {
                                   printf("Can't add KTLS alloc thread %d error %d\n",
                                       domain, error);
                                   return (error);
                           }
                   }
           }
   
           if (bootverbose)
                   printf("KTLS: Initialized %d threads\n", ktls_number_threads);
           return (0);
   }
   
   static int
   ktls_start_kthreads(void)
   {
           int error, state;
   
   start:
           state = atomic_load_acq_int(&ktls_init_state);
           if (__predict_true(state > 0))
                   return (0);
           if (state < 0)
                   return (ENXIO);
   
           sx_xlock(&ktls_init_lock);
           if (ktls_init_state != 0) {
                   sx_xunlock(&ktls_init_lock);
                   goto start;
           }
   
           error = ktls_init();
           if (error == 0)
                   state = 1;
           else
                   state = -1;
           atomic_store_rel_int(&ktls_init_state, state);
           sx_xunlock(&ktls_init_lock);
           return (error);
   }
   
   #if defined(INET) || defined(INET6)
   static int
   ktls_create_session(struct socket *so, struct tls_enable *en,
       struct ktls_session **tlsp, int direction)
   {
           struct ktls_session *tls;
           int error;
   
           /* Only TLS 1.0 - 1.3 are supported. */
           if (en->tls_vmajor != TLS_MAJOR_VER_ONE)
                   return (EINVAL);
           if (en->tls_vminor < TLS_MINOR_VER_ZERO ||
               en->tls_vminor > TLS_MINOR_VER_THREE)
                   return (EINVAL);
   
           if (en->auth_key_len < 0 || en->auth_key_len > TLS_MAX_PARAM_SIZE)
                   return (EINVAL);
           if (en->cipher_key_len < 0 || en->cipher_key_len > TLS_MAX_PARAM_SIZE)
                   return (EINVAL);
           if (en->iv_len < 0 || en->iv_len > sizeof(tls->params.iv))
                   return (EINVAL);
   
           /* All supported algorithms require a cipher key. */
           if (en->cipher_key_len == 0)
                   return (EINVAL);
   
           /* No flags are currently supported. */
           if (en->flags != 0)
                   return (EINVAL);
   
           /* Common checks for supported algorithms. */
           switch (en->cipher_algorithm) {
           case CRYPTO_AES_NIST_GCM_16:
                   /*
                    * auth_algorithm isn't used, but permit GMAC values
                    * for compatibility.
                    */
                   switch (en->auth_algorithm) {
                   case 0:
   #ifdef COMPAT_FREEBSD12
                   /* XXX: Really 13.0-current COMPAT. */
                   case CRYPTO_AES_128_NIST_GMAC:
                   case CRYPTO_AES_192_NIST_GMAC:
                   case CRYPTO_AES_256_NIST_GMAC:
   #endif
                           break;
                   default:
                           return (EINVAL);
                   }
                   if (en->auth_key_len != 0)
                           return (EINVAL);
                   switch (en->tls_vminor) {
                   case TLS_MINOR_VER_TWO:
                           if (en->iv_len != TLS_AEAD_GCM_LEN)
                                   return (EINVAL);
                           break;
                   case TLS_MINOR_VER_THREE:
                           if (en->iv_len != TLS_1_3_GCM_IV_LEN)
                                   return (EINVAL);
                           break;
                   default:
                           return (EINVAL);
                   }
                   break;
           case CRYPTO_AES_CBC:
                   switch (en->auth_algorithm) {
                   case CRYPTO_SHA1_HMAC:
                           break;
                   case CRYPTO_SHA2_256_HMAC:
                   case CRYPTO_SHA2_384_HMAC:
                           if (en->tls_vminor != TLS_MINOR_VER_TWO)
                                   return (EINVAL);
                           break;
                   default:
                           return (EINVAL);
                   }
                   if (en->auth_key_len == 0)
                           return (EINVAL);
   
                   /*
                    * TLS 1.0 requires an implicit IV.  TLS 1.1 and 1.2
                    * use explicit IVs.
                    */
                   switch (en->tls_vminor) {
                   case TLS_MINOR_VER_ZERO:
                           if (en->iv_len != TLS_CBC_IMPLICIT_IV_LEN)
                                   return (EINVAL);
                           break;
                   case TLS_MINOR_VER_ONE:
                   case TLS_MINOR_VER_TWO:
                           /* Ignore any supplied IV. */
                           en->iv_len = 0;
                           break;
                   default:
                           return (EINVAL);
                   }
                   break;
           case CRYPTO_CHACHA20_POLY1305:
                   if (en->auth_algorithm != 0 || en->auth_key_len != 0)
                           return (EINVAL);
                   if (en->tls_vminor != TLS_MINOR_VER_TWO &&
                       en->tls_vminor != TLS_MINOR_VER_THREE)
                           return (EINVAL);
                   if (en->iv_len != TLS_CHACHA20_IV_LEN)
                           return (EINVAL);
                   break;
           default:
                   return (EINVAL);
           }
   
           error = ktls_start_kthreads();
           if (error != 0)
                   return (error);
   
           tls = uma_zalloc(ktls_session_zone, M_WAITOK | M_ZERO);
   
           counter_u64_add(ktls_offload_active, 1);
   
           refcount_init(&tls->refcount, 1);
           if (direction == KTLS_RX)
                   TASK_INIT(&tls->reset_tag_task, 0, ktls_reset_receive_tag, tls);
           else
                   TASK_INIT(&tls->reset_tag_task, 0, ktls_reset_send_tag, tls);
   
           tls->wq_index = ktls_get_cpu(so);
   
           tls->params.cipher_algorithm = en->cipher_algorithm;
           tls->params.auth_algorithm = en->auth_algorithm;
           tls->params.tls_vmajor = en->tls_vmajor;
           tls->params.tls_vminor = en->tls_vminor;
           tls->params.flags = en->flags;
           tls->params.max_frame_len = min(TLS_MAX_MSG_SIZE_V10_2, ktls_maxlen);
   
           /* Set the header and trailer lengths. */
           tls->params.tls_hlen = sizeof(struct tls_record_layer);
           switch (en->cipher_algorithm) {
           case CRYPTO_AES_NIST_GCM_16:
                   /*
                    * TLS 1.2 uses a 4 byte implicit IV with an explicit 8 byte
                    * nonce.  TLS 1.3 uses a 12 byte implicit IV.
                    */
                   if (en->tls_vminor < TLS_MINOR_VER_THREE)
                           tls->params.tls_hlen += sizeof(uint64_t);
                   tls->params.tls_tlen = AES_GMAC_HASH_LEN;
                   tls->params.tls_bs = 1;
                   break;
           case CRYPTO_AES_CBC:
                   switch (en->auth_algorithm) {
                   case CRYPTO_SHA1_HMAC:
                           if (en->tls_vminor == TLS_MINOR_VER_ZERO) {
                                   /* Implicit IV, no nonce. */
                                   tls->sequential_records = true;
                                   tls->next_seqno = be64dec(en->rec_seq);
                                   STAILQ_INIT(&tls->pending_records);
                           } else {
                                   tls->params.tls_hlen += AES_BLOCK_LEN;
                           }
                           tls->params.tls_tlen = AES_BLOCK_LEN +
                               SHA1_HASH_LEN;
                           break;
                   case CRYPTO_SHA2_256_HMAC:
                           tls->params.tls_hlen += AES_BLOCK_LEN;
                           tls->params.tls_tlen = AES_BLOCK_LEN +
                               SHA2_256_HASH_LEN;
                           break;
                   case CRYPTO_SHA2_384_HMAC:
                           tls->params.tls_hlen += AES_BLOCK_LEN;
                           tls->params.tls_tlen = AES_BLOCK_LEN +
                               SHA2_384_HASH_LEN;
                           break;
                   default:
                           panic("invalid hmac");
                   }
                   tls->params.tls_bs = AES_BLOCK_LEN;
                   break;
           case CRYPTO_CHACHA20_POLY1305:
                   /*
                    * Chacha20 uses a 12 byte implicit IV.
                    */
                   tls->params.tls_tlen = POLY1305_HASH_LEN;
                   tls->params.tls_bs = 1;
                   break;
           default:
                   panic("invalid cipher");
           }
   
           /*
            * TLS 1.3 includes optional padding which we do not support,
            * and also puts the "real" record type at the end of the
            * encrypted data.
            */
           if (en->tls_vminor == TLS_MINOR_VER_THREE)
                   tls->params.tls_tlen += sizeof(uint8_t);
   
           KASSERT(tls->params.tls_hlen <= MBUF_PEXT_HDR_LEN,
               ("TLS header length too long: %d", tls->params.tls_hlen));
           KASSERT(tls->params.tls_tlen <= MBUF_PEXT_TRAIL_LEN,
               ("TLS trailer length too long: %d", tls->params.tls_tlen));
   
           if (en->auth_key_len != 0) {
                   tls->params.auth_key_len = en->auth_key_len;
                   tls->params.auth_key = malloc(en->auth_key_len, M_KTLS,
                       M_WAITOK);
                   error = copyin(en->auth_key, tls->params.auth_key,
                       en->auth_key_len);
                   if (error)
                           goto out;
           }
   
           tls->params.cipher_key_len = en->cipher_key_len;
           tls->params.cipher_key = malloc(en->cipher_key_len, M_KTLS, M_WAITOK);
           error = copyin(en->cipher_key, tls->params.cipher_key,
               en->cipher_key_len);
           if (error)
                   goto out;
   
           /*
            * This holds the implicit portion of the nonce for AEAD
            * ciphers and the initial implicit IV for TLS 1.0.  The
            * explicit portions of the IV are generated in ktls_frame().
            */
           if (en->iv_len != 0) {
                   tls->params.iv_len = en->iv_len;
                   error = copyin(en->iv, tls->params.iv, en->iv_len);
                   if (error)
                           goto out;
   
                   /*
                    * For TLS 1.2 with GCM, generate an 8-byte nonce as a
                    * counter to generate unique explicit IVs.
                    *
                    * Store this counter in the last 8 bytes of the IV
                    * array so that it is 8-byte aligned.
                    */
                   if (en->cipher_algorithm == CRYPTO_AES_NIST_GCM_16 &&
                       en->tls_vminor == TLS_MINOR_VER_TWO)
                           arc4rand(tls->params.iv + 8, sizeof(uint64_t), 0);
           }
   
           *tlsp = tls;
           return (0);
   
   out:
           ktls_free(tls);
           return (error);
   }
   
   static struct ktls_session *
   ktls_clone_session(struct ktls_session *tls, int direction)
   {
           struct ktls_session *tls_new;
   
           tls_new = uma_zalloc(ktls_session_zone, M_WAITOK | M_ZERO);
   
           counter_u64_add(ktls_offload_active, 1);
   
           refcount_init(&tls_new->refcount, 1);
           if (direction == KTLS_RX)
                   TASK_INIT(&tls_new->reset_tag_task, 0, ktls_reset_receive_tag,
                       tls_new);
           else
                   TASK_INIT(&tls_new->reset_tag_task, 0, ktls_reset_send_tag,
                       tls_new);
   
           /* Copy fields from existing session. */
           tls_new->params = tls->params;
           tls_new->wq_index = tls->wq_index;
   
           /* Deep copy keys. */
           if (tls_new->params.auth_key != NULL) {
                   tls_new->params.auth_key = malloc(tls->params.auth_key_len,
                       M_KTLS, M_WAITOK);
                   memcpy(tls_new->params.auth_key, tls->params.auth_key,
                       tls->params.auth_key_len);
           }
   
           tls_new->params.cipher_key = malloc(tls->params.cipher_key_len, M_KTLS,
               M_WAITOK);
           memcpy(tls_new->params.cipher_key, tls->params.cipher_key,
               tls->params.cipher_key_len);
   
           return (tls_new);
   }
   
   #ifdef TCP_OFFLOAD
   static int
   ktls_try_toe(struct socket *so, struct ktls_session *tls, int direction)
   {
           struct inpcb *inp;
           struct tcpcb *tp;
           int error;
   
           inp = so->so_pcb;
           INP_WLOCK(inp);
           if (inp->inp_flags & INP_DROPPED) {
                   INP_WUNLOCK(inp);
                   return (ECONNRESET);
           }
           if (inp->inp_socket == NULL) {
                   INP_WUNLOCK(inp);
                   return (ECONNRESET);
           }
           tp = intotcpcb(inp);
           if (!(tp->t_flags & TF_TOE)) {
                   INP_WUNLOCK(inp);
                   return (EOPNOTSUPP);
           }
   
           error = tcp_offload_alloc_tls_session(tp, tls, direction);
           INP_WUNLOCK(inp);
           if (error == 0) {
                   tls->mode = TCP_TLS_MODE_TOE;
                   switch (tls->params.cipher_algorithm) {
                   case CRYPTO_AES_CBC:
                           counter_u64_add(ktls_toe_cbc, 1);
                           break;
                   case CRYPTO_AES_NIST_GCM_16:
                           counter_u64_add(ktls_toe_gcm, 1);
                           break;
                   case CRYPTO_CHACHA20_POLY1305:
                           counter_u64_add(ktls_toe_chacha20, 1);
                           break;
                   }
           }
           return (error);
   }
   #endif
   
   /*
    * Common code used when first enabling ifnet TLS on a connection or
    * when allocating a new ifnet TLS session due to a routing change.
    * This function allocates a new TLS send tag on whatever interface
    * the connection is currently routed over.
    */
   static int
   ktls_alloc_snd_tag(struct inpcb *inp, struct ktls_session *tls, bool force,
       struct m_snd_tag **mstp)
   {
           union if_snd_tag_alloc_params params;
           struct ifnet *ifp;
           struct nhop_object *nh;
           struct tcpcb *tp;
           int error;
   
           INP_RLOCK(inp);
           if (inp->inp_flags & INP_DROPPED) {
                   INP_RUNLOCK(inp);
                   return (ECONNRESET);
           }
           if (inp->inp_socket == NULL) {
                   INP_RUNLOCK(inp);
                   return (ECONNRESET);
           }
           tp = intotcpcb(inp);
   
           /*
            * Check administrative controls on ifnet TLS to determine if
            * ifnet TLS should be denied.
            *
            * - Always permit 'force' requests.
            * - ktls_ifnet_permitted == 0: always deny.
            */
           if (!force && ktls_ifnet_permitted == 0) {
                   INP_RUNLOCK(inp);
                   return (ENXIO);
           }
   
           /*
            * XXX: Use the cached route in the inpcb to find the
            * interface.  This should perhaps instead use
            * rtalloc1_fib(dst, 0, 0, fibnum).  Since KTLS is only
            * enabled after a connection has completed key negotiation in
            * userland, the cached route will be present in practice.
            */
           nh = inp->inp_route.ro_nh;
           if (nh == NULL) {
                   INP_RUNLOCK(inp);
                   return (ENXIO);
           }
           ifp = nh->nh_ifp;
           if_ref(ifp);
   
           /*
            * Allocate a TLS + ratelimit tag if the connection has an
            * existing pacing rate.
            */
           if (tp->t_pacing_rate != -1 &&
               (ifp->if_capenable & IFCAP_TXTLS_RTLMT) != 0) {
                   params.hdr.type = IF_SND_TAG_TYPE_TLS_RATE_LIMIT;
                   params.tls_rate_limit.inp = inp;
                   params.tls_rate_limit.tls = tls;
                   params.tls_rate_limit.max_rate = tp->t_pacing_rate;
           } else {
                   params.hdr.type = IF_SND_TAG_TYPE_TLS;
                   params.tls.inp = inp;
                   params.tls.tls = tls;
           }
           params.hdr.flowid = inp->inp_flowid;
           params.hdr.flowtype = inp->inp_flowtype;
           params.hdr.numa_domain = inp->inp_numa_domain;
           INP_RUNLOCK(inp);
   
           if ((ifp->if_capenable & IFCAP_MEXTPG) == 0) {
                   error = EOPNOTSUPP;
                   goto out;
           }
           if (inp->inp_vflag & INP_IPV6) {
                   if ((ifp->if_capenable & IFCAP_TXTLS6) == 0) {
                           error = EOPNOTSUPP;
                           goto out;
                   }
           } else {
                   if ((ifp->if_capenable & IFCAP_TXTLS4) == 0) {
                           error = EOPNOTSUPP;
                           goto out;
                   }
           }
           error = m_snd_tag_alloc(ifp, &params, mstp);
   out:
           if_rele(ifp);
           return (error);
   }
   
   /*
    * Allocate an initial TLS receive tag for doing HW decryption of TLS
    * data.
    *
    * This function allocates a new TLS receive tag on whatever interface
    * the connection is currently routed over.  If the connection ends up
    * using a different interface for receive this will get fixed up via
    * ktls_input_ifp_mismatch as future packets arrive.
    */
   static int
   ktls_alloc_rcv_tag(struct inpcb *inp, struct ktls_session *tls,
       struct m_snd_tag **mstp)
   {
           union if_snd_tag_alloc_params params;
           struct ifnet *ifp;
           struct nhop_object *nh;
           int error;
   
           if (!ktls_ocf_recrypt_supported(tls))
                   return (ENXIO);
   
           INP_RLOCK(inp);
           if (inp->inp_flags & INP_DROPPED) {
                   INP_RUNLOCK(inp);
                   return (ECONNRESET);
           }
           if (inp->inp_socket == NULL) {
                   INP_RUNLOCK(inp);
                   return (ECONNRESET);
           }
   
           /*
            * Check administrative controls on ifnet TLS to determine if
            * ifnet TLS should be denied.
            */
           if (ktls_ifnet_permitted == 0) {
                   INP_RUNLOCK(inp);
                   return (ENXIO);
           }
   
           /*
            * XXX: As with ktls_alloc_snd_tag, use the cached route in
            * the inpcb to find the interface.
            */
           nh = inp->inp_route.ro_nh;
           if (nh == NULL) {
                   INP_RUNLOCK(inp);
                   return (ENXIO);
           }
           ifp = nh->nh_ifp;
           if_ref(ifp);
           tls->rx_ifp = ifp;
   
           params.hdr.type = IF_SND_TAG_TYPE_TLS_RX;
           params.hdr.flowid = inp->inp_flowid;
           params.hdr.flowtype = inp->inp_flowtype;
           params.hdr.numa_domain = inp->inp_numa_domain;
           params.tls_rx.inp = inp;
           params.tls_rx.tls = tls;
           params.tls_rx.vlan_id = 0;
   
           INP_RUNLOCK(inp);
   
           if (inp->inp_vflag & INP_IPV6) {
                   if ((ifp->if_capenable2 & IFCAP2_RXTLS6) == 0) {
                           error = EOPNOTSUPP;
                           goto out;
                   }
           } else {
                   if ((ifp->if_capenable2 & IFCAP2_RXTLS4) == 0) {
                           error = EOPNOTSUPP;
                           goto out;
                   }
           }
          error = m_snd_tag_alloc(ifp, &params, mstp);
  
          /*
           * If this connection is over a vlan, vlan_snd_tag_alloc
           * rewrites vlan_id with the saved interface.  Save the VLAN
           * ID for use in ktls_reset_receive_tag which allocates new
           * receive tags directly from the leaf interface bypassing
           * if_vlan.
           */
          if (error == 0)
                  tls->rx_vlan_id = params.tls_rx.vlan_id;
  out:
          return (error);
  }
  
  static int
  ktls_try_ifnet(struct socket *so, struct ktls_session *tls, int direction,
      bool force)
  {
          struct m_snd_tag *mst;
          int error;
  
          switch (direction) {
          case KTLS_TX:
                  error = ktls_alloc_snd_tag(so->so_pcb, tls, force, &mst);
                  if (__predict_false(error != 0))
                          goto done;
                  break;
          case KTLS_RX:
                  KASSERT(!force, ("%s: forced receive tag", __func__));
                  error = ktls_alloc_rcv_tag(so->so_pcb, tls, &mst);
                  if (__predict_false(error != 0))
                          goto done;
                  break;
          default:
                  __assert_unreachable();
          }
  
          tls->mode = TCP_TLS_MODE_IFNET;
          tls->snd_tag = mst;
  
          switch (tls->params.cipher_algorithm) {
          case CRYPTO_AES_CBC:
                  counter_u64_add(ktls_ifnet_cbc, 1);
                  break;
          case CRYPTO_AES_NIST_GCM_16:
                  counter_u64_add(ktls_ifnet_gcm, 1);
                  break;
          case CRYPTO_CHACHA20_POLY1305:
                  counter_u64_add(ktls_ifnet_chacha20, 1);
                  break;
          default:
                  break;
          }
  done:
          return (error);
  }
  
  static void
  ktls_use_sw(struct ktls_session *tls)
  {
          tls->mode = TCP_TLS_MODE_SW;
          switch (tls->params.cipher_algorithm) {
          case CRYPTO_AES_CBC:
                  counter_u64_add(ktls_sw_cbc, 1);
                  break;
          case CRYPTO_AES_NIST_GCM_16:
                  counter_u64_add(ktls_sw_gcm, 1);
                  break;
          case CRYPTO_CHACHA20_POLY1305:
                  counter_u64_add(ktls_sw_chacha20, 1);
                  break;
          }
  }
  
  static int
  ktls_try_sw(struct socket *so, struct ktls_session *tls, int direction)
  {
          int error;
  
          error = ktls_ocf_try(so, tls, direction);
          if (error)
                  return (error);
          ktls_use_sw(tls);
          return (0);
  }
  
  /*
   * KTLS RX stores data in the socket buffer as a list of TLS records,
   * where each record is stored as a control message containg the TLS
   * header followed by data mbufs containing the decrypted data.  This
   * is different from KTLS TX which always uses an mb_ext_pgs mbuf for
   * both encrypted and decrypted data.  TLS records decrypted by a NIC
   * should be queued to the socket buffer as records, but encrypted
   * data which needs to be decrypted by software arrives as a stream of
   * regular mbufs which need to be converted.  In addition, there may
   * already be pending encrypted data in the socket buffer when KTLS RX
   * is enabled.
   *
   * To manage not-yet-decrypted data for KTLS RX, the following scheme
   * is used:
   *
   * - A single chain of NOTREADY mbufs is hung off of sb_mtls.
   *
   * - ktls_check_rx checks this chain of mbufs reading the TLS header
   *   from the first mbuf.  Once all of the data for that TLS record is
   *   queued, the socket is queued to a worker thread.
   *
   * - The worker thread calls ktls_decrypt to decrypt TLS records in
   *   the TLS chain.  Each TLS record is detached from the TLS chain,
   *   decrypted, and inserted into the regular socket buffer chain as
   *   record starting with a control message holding the TLS header and
   *   a chain of mbufs holding the encrypted data.
   */
  
  static void
  sb_mark_notready(struct sockbuf *sb)
  {
          struct mbuf *m;
  
          m = sb->sb_mb;
          sb->sb_mtls = m;
          sb->sb_mb = NULL;
          sb->sb_mbtail = NULL;
          sb->sb_lastrecord = NULL;
          for (; m != NULL; m = m->m_next) {
                  KASSERT(m->m_nextpkt == NULL, ("%s: m_nextpkt != NULL",
                      __func__));
                  KASSERT((m->m_flags & M_NOTAVAIL) == 0, ("%s: mbuf not avail",
                      __func__));
                  KASSERT(sb->sb_acc >= m->m_len, ("%s: sb_acc < m->m_len",
                      __func__));
                  m->m_flags |= M_NOTREADY;
                  sb->sb_acc -= m->m_len;
                  sb->sb_tlscc += m->m_len;
                  sb->sb_mtlstail = m;
          }
          KASSERT(sb->sb_acc == 0 && sb->sb_tlscc == sb->sb_ccc,
              ("%s: acc %u tlscc %u ccc %u", __func__, sb->sb_acc, sb->sb_tlscc,
              sb->sb_ccc));
  }
  
  /*
   * Return information about the pending TLS data in a socket
   * buffer.  On return, 'seqno' is set to the sequence number
   * of the next TLS record to be received, 'resid' is set to
   * the amount of bytes still needed for the last pending
   * record.  The function returns 'false' if the last pending
   * record contains a partial TLS header.  In that case, 'resid'
   * is the number of bytes needed to complete the TLS header.
   */
  bool
  ktls_pending_rx_info(struct sockbuf *sb, uint64_t *seqnop, size_t *residp)
  {
          struct tls_record_layer hdr;
          struct mbuf *m;
          uint64_t seqno;
          size_t resid;
          u_int offset, record_len;
  
          SOCKBUF_LOCK_ASSERT(sb);
          MPASS(sb->sb_flags & SB_TLS_RX);
          seqno = sb->sb_tls_seqno;
          resid = sb->sb_tlscc;
          m = sb->sb_mtls;
          offset = 0;
  
          if (resid == 0) {
                  *seqnop = seqno;
                  *residp = 0;
                  return (true);
          }
  
          for (;;) {
                  seqno++;
  
                  if (resid < sizeof(hdr)) {
                          *seqnop = seqno;
                          *residp = sizeof(hdr) - resid;
                          return (false);
                  }
  
                  m_copydata(m, offset, sizeof(hdr), (void *)&hdr);
  
                  record_len = sizeof(hdr) + ntohs(hdr.tls_length);
                  if (resid <= record_len) {
                          *seqnop = seqno;
                          *residp = record_len - resid;
                          return (true);
                  }
                  resid -= record_len;
  
                  while (record_len != 0) {
                          if (m->m_len - offset > record_len) {
                                  offset += record_len;
                                  break;
                          }
  
                          record_len -= (m->m_len - offset);
                          offset = 0;
                          m = m->m_next;
                  }
          }
  }
  
  int
  ktls_enable_rx(struct socket *so, struct tls_enable *en)
  {
          struct ktls_session *tls;
          int error;
  
          if (!ktls_offload_enable)
                  return (ENOTSUP);
          if (SOLISTENING(so))
                  return (EINVAL);
  
          counter_u64_add(ktls_offload_enable_calls, 1);
  
          /*
           * This should always be true since only the TCP socket option
           * invokes this function.
           */
          if (so->so_proto->pr_protocol != IPPROTO_TCP)
                  return (EINVAL);
  
          /*
           * XXX: Don't overwrite existing sessions.  We should permit
           * this to support rekeying in the future.
           */
          if (so->so_rcv.sb_tls_info != NULL)
                  return (EALREADY);
  
          if (en->cipher_algorithm == CRYPTO_AES_CBC && !ktls_cbc_enable)
                  return (ENOTSUP);
  
          error = ktls_create_session(so, en, &tls, KTLS_RX);
          if (error)
                  return (error);
  
          error = ktls_ocf_try(so, tls, KTLS_RX);
          if (error) {
                  ktls_free(tls);
                  return (error);
          }
  
          /* Mark the socket as using TLS offload. */
          SOCKBUF_LOCK(&so->so_rcv);
          so->so_rcv.sb_tls_seqno = be64dec(en->rec_seq);
          so->so_rcv.sb_tls_info = tls;
          so->so_rcv.sb_flags |= SB_TLS_RX;
  
          /* Mark existing data as not ready until it can be decrypted. */
          sb_mark_notready(&so->so_rcv);
          ktls_check_rx(&so->so_rcv);
          SOCKBUF_UNLOCK(&so->so_rcv);
  
          /* Prefer TOE -> ifnet TLS -> software TLS. */
  #ifdef TCP_OFFLOAD
          error = ktls_try_toe(so, tls, KTLS_RX);
          if (error)
  #endif
                  error = ktls_try_ifnet(so, tls, KTLS_RX, false);
          if (error)
                  ktls_use_sw(tls);
  
          counter_u64_add(ktls_offload_total, 1);
  
          return (0);
  }
  
  int
  ktls_enable_tx(struct socket *so, struct tls_enable *en)
  {
          struct ktls_session *tls;
          struct inpcb *inp;
          int error;
  
          if (!ktls_offload_enable)
                  return (ENOTSUP);
          if (SOLISTENING(so))
                  return (EINVAL);
  
          counter_u64_add(ktls_offload_enable_calls, 1);
  
          /*
           * This should always be true since only the TCP socket option
           * invokes this function.
           */
          if (so->so_proto->pr_protocol != IPPROTO_TCP)
                  return (EINVAL);
  
          /*
           * XXX: Don't overwrite existing sessions.  We should permit
           * this to support rekeying in the future.
           */
          if (so->so_snd.sb_tls_info != NULL)
                  return (EALREADY);
  
          if (en->cipher_algorithm == CRYPTO_AES_CBC && !ktls_cbc_enable)
                  return (ENOTSUP);
  
          /* TLS requires ext pgs */
          if (mb_use_ext_pgs == 0)
                  return (ENXIO);
  
          error = ktls_create_session(so, en, &tls, KTLS_TX);
          if (error)
                  return (error);
  
          /* Prefer TOE -> ifnet TLS -> software TLS. */
  #ifdef TCP_OFFLOAD
          error = ktls_try_toe(so, tls, KTLS_TX);
          if (error)
  #endif
                  error = ktls_try_ifnet(so, tls, KTLS_TX, false);
          if (error)
                  error = ktls_try_sw(so, tls, KTLS_TX);
  
          if (error) {
                  ktls_free(tls);
                  return (error);
          }
  
          error = SOCK_IO_SEND_LOCK(so, SBL_WAIT);
          if (error) {
                  ktls_free(tls);
                  return (error);
          }
  
          /*
           * Write lock the INP when setting sb_tls_info so that
           * routines in tcp_ratelimit.c can read sb_tls_info while
           * holding the INP lock.
           */
          inp = so->so_pcb;
          INP_WLOCK(inp);
          SOCKBUF_LOCK(&so->so_snd);
          so->so_snd.sb_tls_seqno = be64dec(en->rec_seq);
          so->so_snd.sb_tls_info = tls;
          if (tls->mode != TCP_TLS_MODE_SW)
                  so->so_snd.sb_flags |= SB_TLS_IFNET;
          SOCKBUF_UNLOCK(&so->so_snd);
          INP_WUNLOCK(inp);
          SOCK_IO_SEND_UNLOCK(so);
  
          counter_u64_add(ktls_offload_total, 1);
  
          return (0);
  }
  
  int
  ktls_get_rx_mode(struct socket *so, int *modep)
  {
          struct ktls_session *tls;
          struct inpcb *inp __diagused;
  
          if (SOLISTENING(so))
                  return (EINVAL);
          inp = so->so_pcb;
          INP_WLOCK_ASSERT(inp);
          SOCK_RECVBUF_LOCK(so);
          tls = so->so_rcv.sb_tls_info;
          if (tls == NULL)
                  *modep = TCP_TLS_MODE_NONE;
          else
                  *modep = tls->mode;
          SOCK_RECVBUF_UNLOCK(so);
          return (0);
  }
  
  /*
   * ktls_get_rx_sequence - get the next TCP- and TLS- sequence number.
   *
   * This function gets information about the next TCP- and TLS-
   * sequence number to be processed by the TLS receive worker
   * thread. The information is extracted from the given "inpcb"
   * structure. The values are stored in host endian format at the two
   * given output pointer locations. The TCP sequence number points to
   * the beginning of the TLS header.
   *
   * This function returns zero on success, else a non-zero error code
   * is returned.
   */
  int
  ktls_get_rx_sequence(struct inpcb *inp, uint32_t *tcpseq, uint64_t *tlsseq)
  {
          struct socket *so;
          struct tcpcb *tp;
  
          INP_RLOCK(inp);
          so = inp->inp_socket;
          if (__predict_false(so == NULL)) {
                  INP_RUNLOCK(inp);
                  return (EINVAL);
          }
          if (inp->inp_flags & INP_DROPPED) {
                  INP_RUNLOCK(inp);
                  return (ECONNRESET);
          }
  
          tp = intotcpcb(inp);
          MPASS(tp != NULL);
  
          SOCKBUF_LOCK(&so->so_rcv);
          *tcpseq = tp->rcv_nxt - so->so_rcv.sb_tlscc;
          *tlsseq = so->so_rcv.sb_tls_seqno;
          SOCKBUF_UNLOCK(&so->so_rcv);
  
          INP_RUNLOCK(inp);
  
          return (0);
  }
  
  int
  ktls_get_tx_mode(struct socket *so, int *modep)
  {
          struct ktls_session *tls;
          struct inpcb *inp __diagused;
  
          if (SOLISTENING(so))
                  return (EINVAL);
          inp = so->so_pcb;
          INP_WLOCK_ASSERT(inp);
          SOCK_SENDBUF_LOCK(so);
          tls = so->so_snd.sb_tls_info;
          if (tls == NULL)
                  *modep = TCP_TLS_MODE_NONE;
          else
                  *modep = tls->mode;
          SOCK_SENDBUF_UNLOCK(so);
          return (0);
  }
  
  /*
   * Switch between SW and ifnet TLS sessions as requested.
   */
  int
  ktls_set_tx_mode(struct socket *so, int mode)
  {
          struct ktls_session *tls, *tls_new;
          struct inpcb *inp;
          int error;
  
          if (SOLISTENING(so))
                  return (EINVAL);
          switch (mode) {
          case TCP_TLS_MODE_SW:
          case TCP_TLS_MODE_IFNET:
                  break;
          default:
                  return (EINVAL);
          }
  
          inp = so->so_pcb;
          INP_WLOCK_ASSERT(inp);
          SOCKBUF_LOCK(&so->so_snd);
          tls = so->so_snd.sb_tls_info;
          if (tls == NULL) {
                  SOCKBUF_UNLOCK(&so->so_snd);
                  return (0);
          }
  
          if (tls->mode == mode) {
                  SOCKBUF_UNLOCK(&so->so_snd);
                  return (0);
          }
  
          tls = ktls_hold(tls);
          SOCKBUF_UNLOCK(&so->so_snd);
          INP_WUNLOCK(inp);
  
          tls_new = ktls_clone_session(tls, KTLS_TX);
  
          if (mode == TCP_TLS_MODE_IFNET)
                  error = ktls_try_ifnet(so, tls_new, KTLS_TX, true);
          else
                  error = ktls_try_sw(so, tls_new, KTLS_TX);
          if (error) {
                  counter_u64_add(ktls_switch_failed, 1);
                  ktls_free(tls_new);
                  ktls_free(tls);
                  INP_WLOCK(inp);
                  return (error);
          }
  
          error = SOCK_IO_SEND_LOCK(so, SBL_WAIT);
          if (error) {
                  counter_u64_add(ktls_switch_failed, 1);
                  ktls_free(tls_new);
                  ktls_free(tls);
                  INP_WLOCK(inp);
                  return (error);
          }
  
          /*
           * If we raced with another session change, keep the existing
           * session.
           */
          if (tls != so->so_snd.sb_tls_info) {
                  counter_u64_add(ktls_switch_failed, 1);
                  SOCK_IO_SEND_UNLOCK(so);
                  ktls_free(tls_new);
                  ktls_free(tls);
                  INP_WLOCK(inp);
                  return (EBUSY);
          }
  
          INP_WLOCK(inp);
          SOCKBUF_LOCK(&so->so_snd);
          so->so_snd.sb_tls_info = tls_new;
          if (tls_new->mode != TCP_TLS_MODE_SW)
                  so->so_snd.sb_flags |= SB_TLS_IFNET;
          SOCKBUF_UNLOCK(&so->so_snd);
          SOCK_IO_SEND_UNLOCK(so);
  
          /*
           * Drop two references on 'tls'.  The first is for the
           * ktls_hold() above.  The second drops the reference from the
           * socket buffer.
           */
          KASSERT(tls->refcount >= 2, ("too few references on old session"));
          ktls_free(tls);
          ktls_free(tls);
  
          if (mode == TCP_TLS_MODE_IFNET)
                  counter_u64_add(ktls_switch_to_ifnet, 1);
          else
                  counter_u64_add(ktls_switch_to_sw, 1);
  
          return (0);
  }
  
  /*
   * Try to allocate a new TLS receive tag.  This task is scheduled when
   * sbappend_ktls_rx detects an input path change.  If a new tag is
   * allocated, replace the tag in the TLS session.  If a new tag cannot
   * be allocated, let the session fall back to software decryption.
   */
  static void
  ktls_reset_receive_tag(void *context, int pending)
  {
          union if_snd_tag_alloc_params params;
          struct ktls_session *tls;
          struct m_snd_tag *mst;
          struct inpcb *inp;
          struct ifnet *ifp;
          struct socket *so;
          int error;
  
          MPASS(pending == 1);
  
          tls = context;
          so = tls->so;
          inp = so->so_pcb;
          ifp = NULL;
  
          INP_RLOCK(inp);
          if (inp->inp_flags & INP_DROPPED) {
                  INP_RUNLOCK(inp);
                  goto out;
          }
  
          SOCKBUF_LOCK(&so->so_rcv);
          mst = tls->snd_tag;
          tls->snd_tag = NULL;
          if (mst != NULL)
                  m_snd_tag_rele(mst);
  
          ifp = tls->rx_ifp;
          if_ref(ifp);
          SOCKBUF_UNLOCK(&so->so_rcv);
  
          params.hdr.type = IF_SND_TAG_TYPE_TLS_RX;
          params.hdr.flowid = inp->inp_flowid;
          params.hdr.flowtype = inp->inp_flowtype;
          params.hdr.numa_domain = inp->inp_numa_domain;
          params.tls_rx.inp = inp;
          params.tls_rx.tls = tls;
          params.tls_rx.vlan_id = tls->rx_vlan_id;
          INP_RUNLOCK(inp);
  
          if (inp->inp_vflag & INP_IPV6) {
                  if ((ifp->if_capenable2 & IFCAP2_RXTLS6) == 0)
                          goto out;
          } else {
                  if ((ifp->if_capenable2 & IFCAP2_RXTLS4) == 0)
                          goto out;
          }
  
          error = m_snd_tag_alloc(ifp, &params, &mst);
          if (error == 0) {
                  SOCKBUF_LOCK(&so->so_rcv);
                  tls->snd_tag = mst;
                  SOCKBUF_UNLOCK(&so->so_rcv);
  
                  counter_u64_add(ktls_ifnet_reset, 1);
          } else {
                  /*
                   * Just fall back to software decryption if a tag
                   * cannot be allocated leaving the connection intact.
                   * If a future input path change switches to another
                   * interface this connection will resume ifnet TLS.
                   */
                  counter_u64_add(ktls_ifnet_reset_failed, 1);
          }
  
  out:
          mtx_pool_lock(mtxpool_sleep, tls);
          tls->reset_pending = false;
          mtx_pool_unlock(mtxpool_sleep, tls);
  
          if (ifp != NULL)
                  if_rele(ifp);
          sorele(so);
          ktls_free(tls);
  }
  
  /*
   * Try to allocate a new TLS send tag.  This task is scheduled when
   * ip_output detects a route change while trying to transmit a packet
   * holding a TLS record.  If a new tag is allocated, replace the tag
   * in the TLS session.  Subsequent packets on the connection will use
   * the new tag.  If a new tag cannot be allocated, drop the
   * connection.
   */
  static void
  ktls_reset_send_tag(void *context, int pending)
  {
          struct epoch_tracker et;
          struct ktls_session *tls;
          struct m_snd_tag *old, *new;
          struct inpcb *inp;
          struct tcpcb *tp;
          int error;
  
          MPASS(pending == 1);
  
          tls = context;
          inp = tls->inp;
  
          /*
           * Free the old tag first before allocating a new one.
           * ip[6]_output_send() will treat a NULL send tag the same as
           * an ifp mismatch and drop packets until a new tag is
           * allocated.
           *
           * Write-lock the INP when changing tls->snd_tag since
           * ip[6]_output_send() holds a read-lock when reading the
           * pointer.
           */
          INP_WLOCK(inp);
          old = tls->snd_tag;
          tls->snd_tag = NULL;
          INP_WUNLOCK(inp);
          if (old != NULL)
                  m_snd_tag_rele(old);
  
          error = ktls_alloc_snd_tag(inp, tls, true, &new);
  
          if (error == 0) {
                  INP_WLOCK(inp);
                  tls->snd_tag = new;
                  mtx_pool_lock(mtxpool_sleep, tls);
                  tls->reset_pending = false;
                  mtx_pool_unlock(mtxpool_sleep, tls);
                  if (!in_pcbrele_wlocked(inp))
                          INP_WUNLOCK(inp);
  
                  counter_u64_add(ktls_ifnet_reset, 1);
  
                  /*
                   * XXX: Should we kick tcp_output explicitly now that
                   * the send tag is fixed or just rely on timers?
                   */
          } else {
                  NET_EPOCH_ENTER(et);
                  INP_WLOCK(inp);
                  if (!in_pcbrele_wlocked(inp)) {
                          if (!(inp->inp_flags & INP_DROPPED)) {
                                  tp = intotcpcb(inp);
                                  CURVNET_SET(inp->inp_vnet);
                                  tp = tcp_drop(tp, ECONNABORTED);
                                  CURVNET_RESTORE();
                                  if (tp != NULL)
                                          INP_WUNLOCK(inp);
                                  counter_u64_add(ktls_ifnet_reset_dropped, 1);
                          } else
                                  INP_WUNLOCK(inp);
                  }
                  NET_EPOCH_EXIT(et);
  
                  counter_u64_add(ktls_ifnet_reset_failed, 1);
  
                  /*
                   * Leave reset_pending true to avoid future tasks while
                   * the socket goes away.
                   */
          }
  
          ktls_free(tls);
  }
  
  void
  ktls_input_ifp_mismatch(struct sockbuf *sb, struct ifnet *ifp)
  {
          struct ktls_session *tls;
          struct socket *so;
  
          SOCKBUF_LOCK_ASSERT(sb);
          KASSERT(sb->sb_flags & SB_TLS_RX, ("%s: sockbuf %p isn't TLS RX",
              __func__, sb));
          so = __containerof(sb, struct socket, so_rcv);
  
          tls = sb->sb_tls_info;
          if_rele(tls->rx_ifp);
          if_ref(ifp);
          tls->rx_ifp = ifp;
  
          /*
           * See if we should schedule a task to update the receive tag for
           * this session.
           */
          mtx_pool_lock(mtxpool_sleep, tls);
          if (!tls->reset_pending) {
                  (void) ktls_hold(tls);
                  soref(so);
                  tls->so = so;
                  tls->reset_pending = true;
                  taskqueue_enqueue(taskqueue_thread, &tls->reset_tag_task);
          }
          mtx_pool_unlock(mtxpool_sleep, tls);
  }
  
  int
  ktls_output_eagain(struct inpcb *inp, struct ktls_session *tls)
  {
  
          if (inp == NULL)
                  return (ENOBUFS);
  
          INP_LOCK_ASSERT(inp);
  
          /*
           * See if we should schedule a task to update the send tag for
           * this session.
           */
          mtx_pool_lock(mtxpool_sleep, tls);
          if (!tls->reset_pending) {
                  (void) ktls_hold(tls);
                  in_pcbref(inp);
                  tls->inp = inp;
                  tls->reset_pending = true;
                  taskqueue_enqueue(taskqueue_thread, &tls->reset_tag_task);
          }
          mtx_pool_unlock(mtxpool_sleep, tls);
          return (ENOBUFS);
  }
  
  #ifdef RATELIMIT
  int
  ktls_modify_txrtlmt(struct ktls_session *tls, uint64_t max_pacing_rate)
  {
          union if_snd_tag_modify_params params = {
                  .rate_limit.max_rate = max_pacing_rate,
                  .rate_limit.flags = M_NOWAIT,
          };
          struct m_snd_tag *mst;
  
          /* Can't get to the inp, but it should be locked. */
          /* INP_LOCK_ASSERT(inp); */
  
          MPASS(tls->mode == TCP_TLS_MODE_IFNET);
  
          if (tls->snd_tag == NULL) {
                  /*
                   * Resetting send tag, ignore this change.  The
                   * pending reset may or may not see this updated rate
                   * in the tcpcb.  If it doesn't, we will just lose
                   * this rate change.
                   */
                  return (0);
          }
  
          mst = tls->snd_tag;
  
          MPASS(mst != NULL);
          MPASS(mst->sw->type == IF_SND_TAG_TYPE_TLS_RATE_LIMIT);
  
          return (mst->sw->snd_tag_modify(mst, &params));
  }
  #endif
  #endif
  
  void
  ktls_destroy(struct ktls_session *tls)
  {
          MPASS(tls->refcount == 0);
  
          if (tls->sequential_records) {
                  struct mbuf *m, *n;
                  int page_count;
  
                  STAILQ_FOREACH_SAFE(m, &tls->pending_records, m_epg_stailq, n) {
                          page_count = m->m_epg_enc_cnt;
                          while (page_count > 0) {
                                  KASSERT(page_count >= m->m_epg_nrdy,
                                      ("%s: too few pages", __func__));
                                  page_count -= m->m_epg_nrdy;
                                  m = m_free(m);
                          }
                  }
          }
  
          counter_u64_add(ktls_offload_active, -1);
          switch (tls->mode) {
          case TCP_TLS_MODE_SW:
                  switch (tls->params.cipher_algorithm) {
                  case CRYPTO_AES_CBC:
                          counter_u64_add(ktls_sw_cbc, -1);
                          break;
                  case CRYPTO_AES_NIST_GCM_16:
                          counter_u64_add(ktls_sw_gcm, -1);
                          break;
                  case CRYPTO_CHACHA20_POLY1305:
                          counter_u64_add(ktls_sw_chacha20, -1);
                          break;
                  }
                  break;
          case TCP_TLS_MODE_IFNET:
                  switch (tls->params.cipher_algorithm) {
                  case CRYPTO_AES_CBC:
                          counter_u64_add(ktls_ifnet_cbc, -1);
                          break;
                  case CRYPTO_AES_NIST_GCM_16:
                          counter_u64_add(ktls_ifnet_gcm, -1);
                          break;
                  case CRYPTO_CHACHA20_POLY1305:
                          counter_u64_add(ktls_ifnet_chacha20, -1);
                          break;
                  }
                  if (tls->snd_tag != NULL)
                          m_snd_tag_rele(tls->snd_tag);
                  if (tls->rx_ifp != NULL)
                          if_rele(tls->rx_ifp);
                  break;
  #ifdef TCP_OFFLOAD
          case TCP_TLS_MODE_TOE:
                  switch (tls->params.cipher_algorithm) {
                  case CRYPTO_AES_CBC:
                          counter_u64_add(ktls_toe_cbc, -1);
                          break;
                  case CRYPTO_AES_NIST_GCM_16:
                          counter_u64_add(ktls_toe_gcm, -1);
                          break;
                  case CRYPTO_CHACHA20_POLY1305:
                          counter_u64_add(ktls_toe_chacha20, -1);
                          break;
                  }
                  break;
  #endif
          }
          if (tls->ocf_session != NULL)
                  ktls_ocf_free(tls);
          if (tls->params.auth_key != NULL) {
                  zfree(tls->params.auth_key, M_KTLS);
                  tls->params.auth_key = NULL;
                  tls->params.auth_key_len = 0;
          }
          if (tls->params.cipher_key != NULL) {
                  zfree(tls->params.cipher_key, M_KTLS);
                  tls->params.cipher_key = NULL;
                  tls->params.cipher_key_len = 0;
          }
          explicit_bzero(tls->params.iv, sizeof(tls->params.iv));
  
          uma_zfree(ktls_session_zone, tls);
  }
  
  void
  ktls_seq(struct sockbuf *sb, struct mbuf *m)
  {
  
          for (; m != NULL; m = m->m_next) {
                  KASSERT((m->m_flags & M_EXTPG) != 0,
                      ("ktls_seq: mapped mbuf %p", m));
  
                  m->m_epg_seqno = sb->sb_tls_seqno;
                  sb->sb_tls_seqno++;
          }
  }
  
  /*
   * Add TLS framing (headers and trailers) to a chain of mbufs.  Each
   * mbuf in the chain must be an unmapped mbuf.  The payload of the
   * mbuf must be populated with the payload of each TLS record.
   *
   * The record_type argument specifies the TLS record type used when
   * populating the TLS header.
   *
   * The enq_count argument on return is set to the number of pages of
   * payload data for this entire chain that need to be encrypted via SW
   * encryption.  The returned value should be passed to ktls_enqueue
   * when scheduling encryption of this chain of mbufs.  To handle the
   * special case of empty fragments for TLS 1.0 sessions, an empty
   * fragment counts as one page.
   */
  void
  ktls_frame(struct mbuf *top, struct ktls_session *tls, int *enq_cnt,
      uint8_t record_type)
  {
          struct tls_record_layer *tlshdr;
          struct mbuf *m;
          uint64_t *noncep;
          uint16_t tls_len;
          int maxlen __diagused;
  
          maxlen = tls->params.max_frame_len;
          *enq_cnt = 0;
          for (m = top; m != NULL; m = m->m_next) {
                  /*
                   * All mbufs in the chain should be TLS records whose
                   * payload does not exceed the maximum frame length.
                   *
                   * Empty TLS 1.0 records are permitted when using CBC.
                   */
                  KASSERT(m->m_len <= maxlen && m->m_len >= 0 &&
                      (m->m_len > 0 || ktls_permit_empty_frames(tls)),
                      ("ktls_frame: m %p len %d", m, m->m_len));
  
                  /*
                   * TLS frames require unmapped mbufs to store session
                   * info.
                   */
                  KASSERT((m->m_flags & M_EXTPG) != 0,
                      ("ktls_frame: mapped mbuf %p (top = %p)", m, top));
  
                  tls_len = m->m_len;
  
                  /* Save a reference to the session. */
                  m->m_epg_tls = ktls_hold(tls);
  
                  m->m_epg_hdrlen = tls->params.tls_hlen;
                  m->m_epg_trllen = tls->params.tls_tlen;
                  if (tls->params.cipher_algorithm == CRYPTO_AES_CBC) {
                          int bs, delta;
  
                          /*
                           * AES-CBC pads messages to a multiple of the
                           * block size.  Note that the padding is
                           * applied after the digest and the encryption
                           * is done on the "plaintext || mac || padding".
                           * At least one byte of padding is always
                           * present.
                           *
                           * Compute the final trailer length assuming
                           * at most one block of padding.
                           * tls->params.tls_tlen is the maximum
                           * possible trailer length (padding + digest).
                           * delta holds the number of excess padding
                           * bytes if the maximum were used.  Those
                           * extra bytes are removed.
                           */
                          bs = tls->params.tls_bs;
                          delta = (tls_len + tls->params.tls_tlen) & (bs - 1);
                          m->m_epg_trllen -= delta;
                  }
                  m->m_len += m->m_epg_hdrlen + m->m_epg_trllen;
  
                  /* Populate the TLS header. */
                  tlshdr = (void *)m->m_epg_hdr;
                  tlshdr->tls_vmajor = tls->params.tls_vmajor;
  
                  /*
                   * TLS 1.3 masquarades as TLS 1.2 with a record type
                   * of TLS_RLTYPE_APP.
                   */
                  if (tls->params.tls_vminor == TLS_MINOR_VER_THREE &&
                      tls->params.tls_vmajor == TLS_MAJOR_VER_ONE) {
                          tlshdr->tls_vminor = TLS_MINOR_VER_TWO;
                          tlshdr->tls_type = TLS_RLTYPE_APP;
                          /* save the real record type for later */
                          m->m_epg_record_type = record_type;
                          m->m_epg_trail[0] = record_type;
                  } else {
                          tlshdr->tls_vminor = tls->params.tls_vminor;
                          tlshdr->tls_type = record_type;
                  }
                  tlshdr->tls_length = htons(m->m_len - sizeof(*tlshdr));
  
                  /*
                   * Store nonces / explicit IVs after the end of the
                   * TLS header.
                   *
                   * For GCM with TLS 1.2, an 8 byte nonce is copied
                   * from the end of the IV.  The nonce is then
                   * incremented for use by the next record.
                   *
                   * For CBC, a random nonce is inserted for TLS 1.1+.
                   */
                  if (tls->params.cipher_algorithm == CRYPTO_AES_NIST_GCM_16 &&
                      tls->params.tls_vminor == TLS_MINOR_VER_TWO) {
                          noncep = (uint64_t *)(tls->params.iv + 8);
                          be64enc(tlshdr + 1, *noncep);
                          (*noncep)++;
                  } else if (tls->params.cipher_algorithm == CRYPTO_AES_CBC &&
                      tls->params.tls_vminor >= TLS_MINOR_VER_ONE)
                          arc4rand(tlshdr + 1, AES_BLOCK_LEN, 0);
  
                  /*
                   * When using SW encryption, mark the mbuf not ready.
                   * It will be marked ready via sbready() after the
                   * record has been encrypted.
                   *
                   * When using ifnet TLS, unencrypted TLS records are
                   * sent down the stack to the NIC.
                   */
                  if (tls->mode == TCP_TLS_MODE_SW) {
                          m->m_flags |= M_NOTREADY;
                          if (__predict_false(tls_len == 0)) {
                                  /* TLS 1.0 empty fragment. */
                                  m->m_epg_nrdy = 1;
                          } else
                                  m->m_epg_nrdy = m->m_epg_npgs;
                          *enq_cnt += m->m_epg_nrdy;
                  }
          }
  }
  
  bool
  ktls_permit_empty_frames(struct ktls_session *tls)
  {
          return (tls->params.cipher_algorithm == CRYPTO_AES_CBC &&
              tls->params.tls_vminor == TLS_MINOR_VER_ZERO);
  }
  
  void
  ktls_check_rx(struct sockbuf *sb)
  {
          struct tls_record_layer hdr;
          struct ktls_wq *wq;
          struct socket *so;
          bool running;
  
          SOCKBUF_LOCK_ASSERT(sb);
          KASSERT(sb->sb_flags & SB_TLS_RX, ("%s: sockbuf %p isn't TLS RX",
              __func__, sb));
          so = __containerof(sb, struct socket, so_rcv);
  
          if (sb->sb_flags & SB_TLS_RX_RUNNING)
                  return;
  
          /* Is there enough queued for a TLS header? */
          if (sb->sb_tlscc < sizeof(hdr)) {
                  if ((sb->sb_state & SBS_CANTRCVMORE) != 0 && sb->sb_tlscc != 0)
                          so->so_error = EMSGSIZE;
                  return;
          }
  
          m_copydata(sb->sb_mtls, 0, sizeof(hdr), (void *)&hdr);
  
          /* Is the entire record queued? */
          if (sb->sb_tlscc < sizeof(hdr) + ntohs(hdr.tls_length)) {
                  if ((sb->sb_state & SBS_CANTRCVMORE) != 0)
                          so->so_error = EMSGSIZE;
                  return;
          }
  
          sb->sb_flags |= SB_TLS_RX_RUNNING;
  
          soref(so);
          wq = &ktls_wq[so->so_rcv.sb_tls_info->wq_index];
          mtx_lock(&wq->mtx);
          STAILQ_INSERT_TAIL(&wq->so_head, so, so_ktls_rx_list);
          running = wq->running;
          mtx_unlock(&wq->mtx);
          if (!running)
                  wakeup(wq);
          counter_u64_add(ktls_cnt_rx_queued, 1);
  }
  
  static struct mbuf *
  ktls_detach_record(struct sockbuf *sb, int len)
  {
          struct mbuf *m, *n, *top;
          int remain;
  
          SOCKBUF_LOCK_ASSERT(sb);
          MPASS(len <= sb->sb_tlscc);
  
          /*
           * If TLS chain is the exact size of the record,
           * just grab the whole record.
           */
          top = sb->sb_mtls;
          if (sb->sb_tlscc == len) {
                  sb->sb_mtls = NULL;
                  sb->sb_mtlstail = NULL;
                  goto out;
          }
  
          /*
           * While it would be nice to use m_split() here, we need
           * to know exactly what m_split() allocates to update the
           * accounting, so do it inline instead.
           */
          remain = len;
          for (m = top; remain > m->m_len; m = m->m_next)
                  remain -= m->m_len;
  
          /* Easy case: don't have to split 'm'. */
          if (remain == m->m_len) {
                  sb->sb_mtls = m->m_next;
                  if (sb->sb_mtls == NULL)
                          sb->sb_mtlstail = NULL;
                  m->m_next = NULL;
                  goto out;
          }
  
          /*
           * Need to allocate an mbuf to hold the remainder of 'm'.  Try
           * with M_NOWAIT first.
           */
          n = m_get(M_NOWAIT, MT_DATA);
          if (n == NULL) {
                  /*
                   * Use M_WAITOK with socket buffer unlocked.  If
                   * 'sb_mtls' changes while the lock is dropped, return
                   * NULL to force the caller to retry.
                   */
                  SOCKBUF_UNLOCK(sb);
  
                  n = m_get(M_WAITOK, MT_DATA);
  
                  SOCKBUF_LOCK(sb);
                  if (sb->sb_mtls != top) {
                          m_free(n);
                          return (NULL);
                  }
          }
          n->m_flags |= (m->m_flags & (M_NOTREADY | M_DECRYPTED));
  
          /* Store remainder in 'n'. */
          n->m_len = m->m_len - remain;
          if (m->m_flags & M_EXT) {
                  n->m_data = m->m_data + remain;
                  mb_dupcl(n, m);
          } else {
                  bcopy(mtod(m, caddr_t) + remain, mtod(n, caddr_t), n->m_len);
          }
  
          /* Trim 'm' and update accounting. */
          m->m_len -= n->m_len;
          sb->sb_tlscc -= n->m_len;
          sb->sb_ccc -= n->m_len;
  
          /* Account for 'n'. */
          sballoc_ktls_rx(sb, n);
  
          /* Insert 'n' into the TLS chain. */
          sb->sb_mtls = n;
          n->m_next = m->m_next;
          if (sb->sb_mtlstail == m)
                  sb->sb_mtlstail = n;
  
          /* Detach the record from the TLS chain. */
          m->m_next = NULL;
  
  out:
          MPASS(m_length(top, NULL) == len);
          for (m = top; m != NULL; m = m->m_next)
                  sbfree_ktls_rx(sb, m);
          sb->sb_tlsdcc = len;
          sb->sb_ccc += len;
          SBCHECK(sb);
          return (top);
  }
  
  /*
   * Determine the length of the trailing zero padding and find the real
   * record type in the byte before the padding.
   *
   * Walking the mbuf chain backwards is clumsy, so another option would
   * be to scan forwards remembering the last non-zero byte before the
   * trailer.  However, it would be expensive to scan the entire record.
   * Instead, find the last non-zero byte of each mbuf in the chain
   * keeping track of the relative offset of that nonzero byte.
   *
   * trail_len is the size of the MAC/tag on input and is set to the
   * size of the full trailer including padding and the record type on
   * return.
   */
  static int
  tls13_find_record_type(struct ktls_session *tls, struct mbuf *m, int tls_len,
      int *trailer_len, uint8_t *record_typep)
  {
          char *cp;
          u_int digest_start, last_offset, m_len, offset;
          uint8_t record_type;
  
          digest_start = tls_len - *trailer_len;
          last_offset = 0;
          offset = 0;
          for (; m != NULL && offset < digest_start;
               offset += m->m_len, m = m->m_next) {
                  /* Don't look for padding in the tag. */
                  m_len = min(digest_start - offset, m->m_len);
                  cp = mtod(m, char *);
  
                  /* Find last non-zero byte in this mbuf. */
                  while (m_len > 0 && cp[m_len - 1] == 0)
                          m_len--;
                  if (m_len > 0) {
                          record_type = cp[m_len - 1];
                          last_offset = offset + m_len;
                  }
          }
          if (last_offset < tls->params.tls_hlen)
                  return (EBADMSG);
  
          *record_typep = record_type;
          *trailer_len = tls_len - last_offset + 1;
          return (0);
  }
  
  /*
   * Check if a mbuf chain is fully decrypted at the given offset and
   * length. Returns KTLS_MBUF_CRYPTO_ST_DECRYPTED if all data is
   * decrypted. KTLS_MBUF_CRYPTO_ST_MIXED if there is a mix of encrypted
   * and decrypted data. Else KTLS_MBUF_CRYPTO_ST_ENCRYPTED if all data
   * is encrypted.
   */
  ktls_mbuf_crypto_st_t
  ktls_mbuf_crypto_state(struct mbuf *mb, int offset, int len)
  {
          int m_flags_ored = 0;
          int m_flags_anded = -1;
  
          for (; mb != NULL; mb = mb->m_next) {
                  if (offset < mb->m_len)
                          break;
                  offset -= mb->m_len;
          }
          offset += len;
  
          for (; mb != NULL; mb = mb->m_next) {
                  m_flags_ored |= mb->m_flags;
                  m_flags_anded &= mb->m_flags;
  
                  if (offset <= mb->m_len)
                          break;
                  offset -= mb->m_len;
          }
          MPASS(mb != NULL || offset == 0);
  
          if ((m_flags_ored ^ m_flags_anded) & M_DECRYPTED)
                  return (KTLS_MBUF_CRYPTO_ST_MIXED);
          else
                  return ((m_flags_ored & M_DECRYPTED) ?
                      KTLS_MBUF_CRYPTO_ST_DECRYPTED :
                      KTLS_MBUF_CRYPTO_ST_ENCRYPTED);
  }
  
  /*
   * ktls_resync_ifnet - get HW TLS RX back on track after packet loss
   */
  static int
  ktls_resync_ifnet(struct socket *so, uint32_t tls_len, uint64_t tls_rcd_num)
  {
          union if_snd_tag_modify_params params;
          struct m_snd_tag *mst;
          struct inpcb *inp;
          struct tcpcb *tp;
  
          mst = so->so_rcv.sb_tls_info->snd_tag;
          if (__predict_false(mst == NULL))
                  return (EINVAL);
  
          inp = sotoinpcb(so);
          if (__predict_false(inp == NULL))
                  return (EINVAL);
  
          INP_RLOCK(inp);
          if (inp->inp_flags & INP_DROPPED) {
                  INP_RUNLOCK(inp);
                  return (ECONNRESET);
          }
  
          tp = intotcpcb(inp);
          MPASS(tp != NULL);
  
          /* Get the TCP sequence number of the next valid TLS header. */
          SOCKBUF_LOCK(&so->so_rcv);
          params.tls_rx.tls_hdr_tcp_sn =
              tp->rcv_nxt - so->so_rcv.sb_tlscc - tls_len;
          params.tls_rx.tls_rec_length = tls_len;
          params.tls_rx.tls_seq_number = tls_rcd_num;
          SOCKBUF_UNLOCK(&so->so_rcv);
  
          INP_RUNLOCK(inp);
  
          MPASS(mst->sw->type == IF_SND_TAG_TYPE_TLS_RX);
          return (mst->sw->snd_tag_modify(mst, &params));
  }
  
  static void
  ktls_drop(struct socket *so, int error)
  {
          struct epoch_tracker et;
          struct inpcb *inp = sotoinpcb(so);
          struct tcpcb *tp;
  
          NET_EPOCH_ENTER(et);
          INP_WLOCK(inp);
          if (!(inp->inp_flags & INP_DROPPED)) {
                  tp = intotcpcb(inp);
                  CURVNET_SET(inp->inp_vnet);
                  tp = tcp_drop(tp, error);
                  CURVNET_RESTORE();
                  if (tp != NULL)
                          INP_WUNLOCK(inp);
          } else {
                  so->so_error = error;
                  SOCK_RECVBUF_LOCK(so);
                  sorwakeup_locked(so);
                  INP_WUNLOCK(inp);
          }
          NET_EPOCH_EXIT(et);
  }
  
  static void
  ktls_decrypt(struct socket *so)
  {
          char tls_header[MBUF_PEXT_HDR_LEN];
          struct ktls_session *tls;
          struct sockbuf *sb;
          struct tls_record_layer *hdr;
          struct tls_get_record tgr;
          struct mbuf *control, *data, *m;
          ktls_mbuf_crypto_st_t state;
          uint64_t seqno;
          int error, remain, tls_len, trail_len;
          bool tls13;
          uint8_t vminor, record_type;
  
          hdr = (struct tls_record_layer *)tls_header;
          sb = &so->so_rcv;
          SOCKBUF_LOCK(sb);
          KASSERT(sb->sb_flags & SB_TLS_RX_RUNNING,
              ("%s: socket %p not running", __func__, so));
  
          tls = sb->sb_tls_info;
          MPASS(tls != NULL);
  
          tls13 = (tls->params.tls_vminor == TLS_MINOR_VER_THREE);
          if (tls13)
                  vminor = TLS_MINOR_VER_TWO;
          else
                  vminor = tls->params.tls_vminor;
          for (;;) {
                  /* Is there enough queued for a TLS header? */
                  if (sb->sb_tlscc < tls->params.tls_hlen)
                          break;
  
                  m_copydata(sb->sb_mtls, 0, tls->params.tls_hlen, tls_header);
                  tls_len = sizeof(*hdr) + ntohs(hdr->tls_length);
  
                  if (hdr->tls_vmajor != tls->params.tls_vmajor ||
                      hdr->tls_vminor != vminor)
                          error = EINVAL;
                  else if (tls13 && hdr->tls_type != TLS_RLTYPE_APP)
                          error = EINVAL;
                  else if (tls_len < tls->params.tls_hlen || tls_len >
                      tls->params.tls_hlen + TLS_MAX_MSG_SIZE_V10_2 +
                      tls->params.tls_tlen)
                          error = EMSGSIZE;
                  else
                          error = 0;
                  if (__predict_false(error != 0)) {
                          /*
                           * We have a corrupted record and are likely
                           * out of sync.  The connection isn't
                           * recoverable at this point, so abort it.
                           */
                          SOCKBUF_UNLOCK(sb);
                          counter_u64_add(ktls_offload_corrupted_records, 1);
  
                          ktls_drop(so, error);
                          goto deref;
                  }
  
                  /* Is the entire record queued? */
                  if (sb->sb_tlscc < tls_len)
                          break;
  
                  /*
                   * Split out the portion of the mbuf chain containing
                   * this TLS record.
                   */
                  data = ktls_detach_record(sb, tls_len);
                  if (data == NULL)
                          continue;
                  MPASS(sb->sb_tlsdcc == tls_len);
  
                  seqno = sb->sb_tls_seqno;
                  sb->sb_tls_seqno++;
                  SBCHECK(sb);
                  SOCKBUF_UNLOCK(sb);
  
                  /* get crypto state for this TLS record */
                  state = ktls_mbuf_crypto_state(data, 0, tls_len);
  
                  switch (state) {
                  case KTLS_MBUF_CRYPTO_ST_MIXED:
                          error = ktls_ocf_recrypt(tls, hdr, data, seqno);
                          if (error)
                                  break;
                          /* FALLTHROUGH */
                  case KTLS_MBUF_CRYPTO_ST_ENCRYPTED:
                          error = ktls_ocf_decrypt(tls, hdr, data, seqno,
                              &trail_len);
                          if (__predict_true(error == 0)) {
                                  if (tls13) {
                                          error = tls13_find_record_type(tls, data,
                                              tls_len, &trail_len, &record_type);
                                  } else {
                                          record_type = hdr->tls_type;
                                  }
                          }
                          break;
                  case KTLS_MBUF_CRYPTO_ST_DECRYPTED:
                          /*
                           * NIC TLS is only supported for AEAD
                           * ciphersuites which used a fixed sized
                           * trailer.
                           */
                          if (tls13) {
                                  trail_len = tls->params.tls_tlen - 1;
                                  error = tls13_find_record_type(tls, data,
                                      tls_len, &trail_len, &record_type);
                          } else {
                                  trail_len = tls->params.tls_tlen;
                                  error = 0;
                                  record_type = hdr->tls_type;
                          }
                          break;
                  default:
                          error = EINVAL;
                          break;
                  }
                  if (error) {
                          counter_u64_add(ktls_offload_failed_crypto, 1);
  
                          SOCKBUF_LOCK(sb);
                          if (sb->sb_tlsdcc == 0) {
                                  /*
                                   * sbcut/drop/flush discarded these
                                   * mbufs.
                                   */
                                  m_freem(data);
                                  break;
                          }
  
                          /*
                           * Drop this TLS record's data, but keep
                           * decrypting subsequent records.
                           */
                          sb->sb_ccc -= tls_len;
                          sb->sb_tlsdcc = 0;
  
                          if (error != EMSGSIZE)
                                  error = EBADMSG;
                          CURVNET_SET(so->so_vnet);
                          so->so_error = error;
                          sorwakeup_locked(so);
                          CURVNET_RESTORE();
  
                          m_freem(data);
  
                          SOCKBUF_LOCK(sb);
                          continue;
                  }
  
                  /* Allocate the control mbuf. */
                  memset(&tgr, 0, sizeof(tgr));
                  tgr.tls_type = record_type;
                  tgr.tls_vmajor = hdr->tls_vmajor;
                  tgr.tls_vminor = hdr->tls_vminor;
                  tgr.tls_length = htobe16(tls_len - tls->params.tls_hlen -
                      trail_len);
                  control = sbcreatecontrol(&tgr, sizeof(tgr),
                      TLS_GET_RECORD, IPPROTO_TCP, M_WAITOK);
  
                  SOCKBUF_LOCK(sb);
                  if (sb->sb_tlsdcc == 0) {
                          /* sbcut/drop/flush discarded these mbufs. */
                          MPASS(sb->sb_tlscc == 0);
                          m_freem(data);
                          m_freem(control);
                          break;
                  }
  
                  /*
                   * Clear the 'dcc' accounting in preparation for
                   * adding the decrypted record.
                   */
                  sb->sb_ccc -= tls_len;
                  sb->sb_tlsdcc = 0;
                  SBCHECK(sb);
  
                  /* If there is no payload, drop all of the data. */
                  if (tgr.tls_length == htobe16(0)) {
                          m_freem(data);
                          data = NULL;
                  } else {
                          /* Trim header. */
                          remain = tls->params.tls_hlen;
                          while (remain > 0) {
                                  if (data->m_len > remain) {
                                          data->m_data += remain;
                                          data->m_len -= remain;
                                          break;
                                  }
                                  remain -= data->m_len;
                                  data = m_free(data);
                          }
  
                          /* Trim trailer and clear M_NOTREADY. */
                          remain = be16toh(tgr.tls_length);
                          m = data;
                          for (m = data; remain > m->m_len; m = m->m_next) {
                                  m->m_flags &= ~(M_NOTREADY | M_DECRYPTED);
                                  remain -= m->m_len;
                          }
                          m->m_len = remain;
                          m_freem(m->m_next);
                          m->m_next = NULL;
                          m->m_flags &= ~(M_NOTREADY | M_DECRYPTED);
  
                          /* Set EOR on the final mbuf. */
                          m->m_flags |= M_EOR;
                  }
  
                  sbappendcontrol_locked(sb, data, control, 0);
  
                  if (__predict_false(state != KTLS_MBUF_CRYPTO_ST_DECRYPTED)) {
                          sb->sb_flags |= SB_TLS_RX_RESYNC;
                          SOCKBUF_UNLOCK(sb);
                          ktls_resync_ifnet(so, tls_len, seqno);
                          SOCKBUF_LOCK(sb);
                  } else if (__predict_false(sb->sb_flags & SB_TLS_RX_RESYNC)) {
                          sb->sb_flags &= ~SB_TLS_RX_RESYNC;
                          SOCKBUF_UNLOCK(sb);
                          ktls_resync_ifnet(so, 0, seqno);
                          SOCKBUF_LOCK(sb);
                  }
          }
  
          sb->sb_flags &= ~SB_TLS_RX_RUNNING;
  
          if ((sb->sb_state & SBS_CANTRCVMORE) != 0 && sb->sb_tlscc > 0)
                  so->so_error = EMSGSIZE;
  
          sorwakeup_locked(so);
  
  deref:
          SOCKBUF_UNLOCK_ASSERT(sb);
  
          CURVNET_SET(so->so_vnet);
          sorele(so);
          CURVNET_RESTORE();
  }
  
  void
  ktls_enqueue_to_free(struct mbuf *m)
  {
          struct ktls_wq *wq;
          bool running;
  
          /* Mark it for freeing. */
          m->m_epg_flags |= EPG_FLAG_2FREE;
          wq = &ktls_wq[m->m_epg_tls->wq_index];
          mtx_lock(&wq->mtx);
          STAILQ_INSERT_TAIL(&wq->m_head, m, m_epg_stailq);
          running = wq->running;
          mtx_unlock(&wq->mtx);
          if (!running)
                  wakeup(wq);
  }
  
  static void *
  ktls_buffer_alloc(struct ktls_wq *wq, struct mbuf *m)
  {
          void *buf;
          int domain, running;
  
          if (m->m_epg_npgs <= 2)
                  return (NULL);
          if (ktls_buffer_zone == NULL)
                  return (NULL);
          if ((u_int)(ticks - wq->lastallocfail) < hz) {
                  /*
                   * Rate-limit allocation attempts after a failure.
                   * ktls_buffer_import() will acquire a per-domain mutex to check
                   * the free page queues and may fail consistently if memory is
                   * fragmented.
                   */
                  return (NULL);
          }
          buf = uma_zalloc(ktls_buffer_zone, M_NOWAIT | M_NORECLAIM);
          if (buf == NULL) {
                  domain = PCPU_GET(domain);
                  wq->lastallocfail = ticks;
  
                  /*
                   * Note that this check is "racy", but the races are
                   * harmless, and are either a spurious wakeup if
                   * multiple threads fail allocations before the alloc
                   * thread wakes, or waiting an extra second in case we
                   * see an old value of running == true.
                   */
                  if (!VM_DOMAIN_EMPTY(domain)) {
                          running = atomic_load_int(&ktls_domains[domain].alloc_td.running);
                          if (!running)
                                  wakeup(&ktls_domains[domain].alloc_td);
                  }
          }
          return (buf);
  }
  
  static int
  ktls_encrypt_record(struct ktls_wq *wq, struct mbuf *m,
      struct ktls_session *tls, struct ktls_ocf_encrypt_state *state)
  {
          vm_page_t pg;
          int error, i, len, off;
  
          KASSERT((m->m_flags & (M_EXTPG | M_NOTREADY)) == (M_EXTPG | M_NOTREADY),
              ("%p not unready & nomap mbuf\n", m));
          KASSERT(ptoa(m->m_epg_npgs) <= ktls_maxlen,
              ("page count %d larger than maximum frame length %d", m->m_epg_npgs,
              ktls_maxlen));
  
          /* Anonymous mbufs are encrypted in place. */
          if ((m->m_epg_flags & EPG_FLAG_ANON) != 0)
                  return (ktls_ocf_encrypt(state, tls, m, NULL, 0));
  
          /*
           * For file-backed mbufs (from sendfile), anonymous wired
           * pages are allocated and used as the encryption destination.
           */
          if ((state->cbuf = ktls_buffer_alloc(wq, m)) != NULL) {
                  len = ptoa(m->m_epg_npgs - 1) + m->m_epg_last_len -
                      m->m_epg_1st_off;
                  state->dst_iov[0].iov_base = (char *)state->cbuf +
                      m->m_epg_1st_off;
                  state->dst_iov[0].iov_len = len;
                  state->parray[0] = DMAP_TO_PHYS((vm_offset_t)state->cbuf);
                  i = 1;
          } else {
                  off = m->m_epg_1st_off;
                  for (i = 0; i < m->m_epg_npgs; i++, off = 0) {
                          pg = vm_page_alloc_noobj(VM_ALLOC_NODUMP |
                              VM_ALLOC_WIRED | VM_ALLOC_WAITOK);
                          len = m_epg_pagelen(m, i, off);
                          state->parray[i] = VM_PAGE_TO_PHYS(pg);
                          state->dst_iov[i].iov_base =
                              (char *)PHYS_TO_DMAP(state->parray[i]) + off;
                          state->dst_iov[i].iov_len = len;
                  }
          }
          KASSERT(i + 1 <= nitems(state->dst_iov), ("dst_iov is too small"));
          state->dst_iov[i].iov_base = m->m_epg_trail;
          state->dst_iov[i].iov_len = m->m_epg_trllen;
  
          error = ktls_ocf_encrypt(state, tls, m, state->dst_iov, i + 1);
  
          if (__predict_false(error != 0)) {
                  /* Free the anonymous pages. */
                  if (state->cbuf != NULL)
                          uma_zfree(ktls_buffer_zone, state->cbuf);
                  else {
                          for (i = 0; i < m->m_epg_npgs; i++) {
                                  pg = PHYS_TO_VM_PAGE(state->parray[i]);
                                  (void)vm_page_unwire_noq(pg);
                                  vm_page_free(pg);
                          }
                  }
          }
          return (error);
  }
  
  /* Number of TLS records in a batch passed to ktls_enqueue(). */
  static u_int
  ktls_batched_records(struct mbuf *m)
  {
          int page_count, records;
  
          records = 0;
          page_count = m->m_epg_enc_cnt;
          while (page_count > 0) {
                  records++;
                  page_count -= m->m_epg_nrdy;
                  m = m->m_next;
          }
          KASSERT(page_count == 0, ("%s: mismatched page count", __func__));
          return (records);
  }
  
  void
  ktls_enqueue(struct mbuf *m, struct socket *so, int page_count)
  {
          struct ktls_session *tls;
          struct ktls_wq *wq;
          int queued;
          bool running;
  
          KASSERT(((m->m_flags & (M_EXTPG | M_NOTREADY)) ==
              (M_EXTPG | M_NOTREADY)),
              ("ktls_enqueue: %p not unready & nomap mbuf\n", m));
          KASSERT(page_count != 0, ("enqueueing TLS mbuf with zero page count"));
  
          KASSERT(m->m_epg_tls->mode == TCP_TLS_MODE_SW, ("!SW TLS mbuf"));
  
          m->m_epg_enc_cnt = page_count;
  
          /*
           * Save a pointer to the socket.  The caller is responsible
           * for taking an additional reference via soref().
           */
          m->m_epg_so = so;
  
          queued = 1;
          tls = m->m_epg_tls;
          wq = &ktls_wq[tls->wq_index];
          mtx_lock(&wq->mtx);
          if (__predict_false(tls->sequential_records)) {
                  /*
                   * For TLS 1.0, records must be encrypted
                   * sequentially.  For a given connection, all records
                   * queued to the associated work queue are processed
                   * sequentially.  However, sendfile(2) might complete
                   * I/O requests spanning multiple TLS records out of
                   * order.  Here we ensure TLS records are enqueued to
                   * the work queue in FIFO order.
                   *
                   * tls->next_seqno holds the sequence number of the
                   * next TLS record that should be enqueued to the work
                   * queue.  If this next record is not tls->next_seqno,
                   * it must be a future record, so insert it, sorted by
                   * TLS sequence number, into tls->pending_records and
                   * return.
                   *
                   * If this TLS record matches tls->next_seqno, place
                   * it in the work queue and then check
                   * tls->pending_records to see if any
                   * previously-queued records are now ready for
                   * encryption.
                   */
                  if (m->m_epg_seqno != tls->next_seqno) {
                          struct mbuf *n, *p;
  
                          p = NULL;
                          STAILQ_FOREACH(n, &tls->pending_records, m_epg_stailq) {
                                  if (n->m_epg_seqno > m->m_epg_seqno)
                                          break;
                                  p = n;
                          }
                          if (n == NULL)
                                  STAILQ_INSERT_TAIL(&tls->pending_records, m,
                                      m_epg_stailq);
                          else if (p == NULL)
                                  STAILQ_INSERT_HEAD(&tls->pending_records, m,
                                      m_epg_stailq);
                          else
                                  STAILQ_INSERT_AFTER(&tls->pending_records, p, m,
                                      m_epg_stailq);
                          mtx_unlock(&wq->mtx);
                          counter_u64_add(ktls_cnt_tx_pending, 1);
                          return;
                  }
  
                  tls->next_seqno += ktls_batched_records(m);
                  STAILQ_INSERT_TAIL(&wq->m_head, m, m_epg_stailq);
  
                  while (!STAILQ_EMPTY(&tls->pending_records)) {
                          struct mbuf *n;
  
                          n = STAILQ_FIRST(&tls->pending_records);
                          if (n->m_epg_seqno != tls->next_seqno)
                                  break;
  
                          queued++;
                          STAILQ_REMOVE_HEAD(&tls->pending_records, m_epg_stailq);
                          tls->next_seqno += ktls_batched_records(n);
                          STAILQ_INSERT_TAIL(&wq->m_head, n, m_epg_stailq);
                  }
                  counter_u64_add(ktls_cnt_tx_pending, -(queued - 1));
          } else
                  STAILQ_INSERT_TAIL(&wq->m_head, m, m_epg_stailq);
  
          running = wq->running;
          mtx_unlock(&wq->mtx);
          if (!running)
                  wakeup(wq);
          counter_u64_add(ktls_cnt_tx_queued, queued);
  }
  
  /*
   * Once a file-backed mbuf (from sendfile) has been encrypted, free
   * the pages from the file and replace them with the anonymous pages
   * allocated in ktls_encrypt_record().
   */
  static void
  ktls_finish_nonanon(struct mbuf *m, struct ktls_ocf_encrypt_state *state)
  {
          int i;
  
          MPASS((m->m_epg_flags & EPG_FLAG_ANON) == 0);
  
          /* Free the old pages. */
          m->m_ext.ext_free(m);
  
          /* Replace them with the new pages. */
          if (state->cbuf != NULL) {
                  for (i = 0; i < m->m_epg_npgs; i++)
                          m->m_epg_pa[i] = state->parray[0] + ptoa(i);
  
                  /* Contig pages should go back to the cache. */
                  m->m_ext.ext_free = ktls_free_mext_contig;
          } else {
                  for (i = 0; i < m->m_epg_npgs; i++)
                          m->m_epg_pa[i] = state->parray[i];
  
                  /* Use the basic free routine. */
                  m->m_ext.ext_free = mb_free_mext_pgs;
          }
  
          /* Pages are now writable. */
          m->m_epg_flags |= EPG_FLAG_ANON;
  }
  
  static __noinline void
  ktls_encrypt(struct ktls_wq *wq, struct mbuf *top)
  {
          struct ktls_ocf_encrypt_state state;
          struct ktls_session *tls;
          struct socket *so;
          struct mbuf *m;
          int error, npages, total_pages;
  
          so = top->m_epg_so;
          tls = top->m_epg_tls;
          KASSERT(tls != NULL, ("tls = NULL, top = %p\n", top));
          KASSERT(so != NULL, ("so = NULL, top = %p\n", top));
  #ifdef INVARIANTS
          top->m_epg_so = NULL;
  #endif
          total_pages = top->m_epg_enc_cnt;
          npages = 0;
  
          /*
           * Encrypt the TLS records in the chain of mbufs starting with
           * 'top'.  'total_pages' gives us a total count of pages and is
           * used to know when we have finished encrypting the TLS
           * records originally queued with 'top'.
           *
           * NB: These mbufs are queued in the socket buffer and
           * 'm_next' is traversing the mbufs in the socket buffer.  The
           * socket buffer lock is not held while traversing this chain.
           * Since the mbufs are all marked M_NOTREADY their 'm_next'
           * pointers should be stable.  However, the 'm_next' of the
           * last mbuf encrypted is not necessarily NULL.  It can point
           * to other mbufs appended while 'top' was on the TLS work
           * queue.
           *
           * Each mbuf holds an entire TLS record.
           */
          error = 0;
          for (m = top; npages != total_pages; m = m->m_next) {
                  KASSERT(m->m_epg_tls == tls,
                      ("different TLS sessions in a single mbuf chain: %p vs %p",
                      tls, m->m_epg_tls));
                  KASSERT(npages + m->m_epg_npgs <= total_pages,
                      ("page count mismatch: top %p, total_pages %d, m %p", top,
                      total_pages, m));
  
                  error = ktls_encrypt_record(wq, m, tls, &state);
                  if (error) {
                          counter_u64_add(ktls_offload_failed_crypto, 1);
                          break;
                  }
  
                  if ((m->m_epg_flags & EPG_FLAG_ANON) == 0)
                          ktls_finish_nonanon(m, &state);
  
                  npages += m->m_epg_nrdy;
  
                  /*
                   * Drop a reference to the session now that it is no
                   * longer needed.  Existing code depends on encrypted
                   * records having no associated session vs
                   * yet-to-be-encrypted records having an associated
                   * session.
                   */
                  m->m_epg_tls = NULL;
                  ktls_free(tls);
          }
  
          CURVNET_SET(so->so_vnet);
          if (error == 0) {
                  (void)so->so_proto->pr_ready(so, top, npages);
          } else {
                  ktls_drop(so, EIO);
                  mb_free_notready(top, total_pages);
          }
  
          sorele(so);
          CURVNET_RESTORE();
  }
  
  void
  ktls_encrypt_cb(struct ktls_ocf_encrypt_state *state, int error)
  {
          struct ktls_session *tls;
          struct socket *so;
          struct mbuf *m;
          int npages;
  
          m = state->m;
  
          if ((m->m_epg_flags & EPG_FLAG_ANON) == 0)
                  ktls_finish_nonanon(m, state);
  
          so = state->so;
          free(state, M_KTLS);
  
          /*
           * Drop a reference to the session now that it is no longer
           * needed.  Existing code depends on encrypted records having
           * no associated session vs yet-to-be-encrypted records having
           * an associated session.
           */
          tls = m->m_epg_tls;
          m->m_epg_tls = NULL;
          ktls_free(tls);
  
          if (error != 0)
                  counter_u64_add(ktls_offload_failed_crypto, 1);
  
          CURVNET_SET(so->so_vnet);
          npages = m->m_epg_nrdy;
  
          if (error == 0) {
                  (void)so->so_proto->pr_ready(so, m, npages);
          } else {
                  ktls_drop(so, EIO);
                  mb_free_notready(m, npages);
          }
  
          sorele(so);
          CURVNET_RESTORE();
  }
  
  /*
   * Similar to ktls_encrypt, but used with asynchronous OCF backends
   * (coprocessors) where encryption does not use host CPU resources and
   * it can be beneficial to queue more requests than CPUs.
   */
  static __noinline void
  ktls_encrypt_async(struct ktls_wq *wq, struct mbuf *top)
  {
          struct ktls_ocf_encrypt_state *state;
          struct ktls_session *tls;
          struct socket *so;
          struct mbuf *m, *n;
          int error, mpages, npages, total_pages;
  
          so = top->m_epg_so;
          tls = top->m_epg_tls;
          KASSERT(tls != NULL, ("tls = NULL, top = %p\n", top));
          KASSERT(so != NULL, ("so = NULL, top = %p\n", top));
  #ifdef INVARIANTS
          top->m_epg_so = NULL;
  #endif
          total_pages = top->m_epg_enc_cnt;
          npages = 0;
  
          error = 0;
          for (m = top; npages != total_pages; m = n) {
                  KASSERT(m->m_epg_tls == tls,
                      ("different TLS sessions in a single mbuf chain: %p vs %p",
                      tls, m->m_epg_tls));
                  KASSERT(npages + m->m_epg_npgs <= total_pages,
                      ("page count mismatch: top %p, total_pages %d, m %p", top,
                      total_pages, m));
  
                  state = malloc(sizeof(*state), M_KTLS, M_WAITOK | M_ZERO);
                  soref(so);
                  state->so = so;
                  state->m = m;
  
                  mpages = m->m_epg_nrdy;
                  n = m->m_next;
  
                  error = ktls_encrypt_record(wq, m, tls, state);
                  if (error) {
                          counter_u64_add(ktls_offload_failed_crypto, 1);
                          free(state, M_KTLS);
                          CURVNET_SET(so->so_vnet);
                          sorele(so);
                          CURVNET_RESTORE();
                          break;
                  }
  
                  npages += mpages;
          }
  
          CURVNET_SET(so->so_vnet);
          if (error != 0) {
                  ktls_drop(so, EIO);
                  mb_free_notready(m, total_pages - npages);
          }
  
          sorele(so);
          CURVNET_RESTORE();
  }
  
  static int
  ktls_bind_domain(int domain)
  {
          int error;
  
          error = cpuset_setthread(curthread->td_tid, &cpuset_domain[domain]);
          if (error != 0)
                  return (error);
          curthread->td_domain.dr_policy = DOMAINSET_PREF(domain);
          return (0);
  }
  
  static void
  ktls_alloc_thread(void *ctx)
  {
          struct ktls_domain_info *ktls_domain = ctx;
          struct ktls_alloc_thread *sc = &ktls_domain->alloc_td;
          void **buf;
          struct sysctl_oid *oid;
          char name[80];
          int domain, error, i, nbufs;
  
          domain = ktls_domain - ktls_domains;
          if (bootverbose)
                  printf("Starting KTLS alloc thread for domain %d\n", domain);
          error = ktls_bind_domain(domain);
          if (error)
                  printf("Unable to bind KTLS alloc thread for domain %d: error %d\n",
                      domain, error);
          snprintf(name, sizeof(name), "domain%d", domain);
          oid = SYSCTL_ADD_NODE(NULL, SYSCTL_STATIC_CHILDREN(_kern_ipc_tls), OID_AUTO,
              name, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "");
          SYSCTL_ADD_U64(NULL, SYSCTL_CHILDREN(oid), OID_AUTO, "allocs",
              CTLFLAG_RD,  &sc->allocs, 0, "buffers allocated");
          SYSCTL_ADD_U64(NULL, SYSCTL_CHILDREN(oid), OID_AUTO, "wakeups",
              CTLFLAG_RD,  &sc->wakeups, 0, "thread wakeups");
          SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(oid), OID_AUTO, "running",
              CTLFLAG_RD,  &sc->running, 0, "thread running");
  
          buf = NULL;
          nbufs = 0;
          for (;;) {
                  atomic_store_int(&sc->running, 0);
                  tsleep(sc, PZERO | PNOLOCK, "-",  0);
                  atomic_store_int(&sc->running, 1);
                  sc->wakeups++;
                  if (nbufs != ktls_max_alloc) {
                          free(buf, M_KTLS);
                          nbufs = atomic_load_int(&ktls_max_alloc);
                          buf = malloc(sizeof(void *) * nbufs, M_KTLS,
                              M_WAITOK | M_ZERO);
                  }
                  /*
                   * Below we allocate nbufs with different allocation
                   * flags than we use when allocating normally during
                   * encryption in the ktls worker thread.  We specify
                   * M_NORECLAIM in the worker thread. However, we omit
                   * that flag here and add M_WAITOK so that the VM
                   * system is permitted to perform expensive work to
                   * defragment memory.  We do this here, as it does not
                   * matter if this thread blocks.  If we block a ktls
                   * worker thread, we risk developing backlogs of
                   * buffers to be encrypted, leading to surges of
                   * traffic and potential NIC output drops.
                   */
                  for (i = 0; i < nbufs; i++) {
                          buf[i] = uma_zalloc(ktls_buffer_zone, M_WAITOK);
                          sc->allocs++;
                  }
                  for (i = 0; i < nbufs; i++) {
                          uma_zfree(ktls_buffer_zone, buf[i]);
                          buf[i] = NULL;
                  }
          }
  }
  
  static void
  ktls_work_thread(void *ctx)
  {
          struct ktls_wq *wq = ctx;
          struct mbuf *m, *n;
          struct socket *so, *son;
          STAILQ_HEAD(, mbuf) local_m_head;
          STAILQ_HEAD(, socket) local_so_head;
          int cpu;
  
          cpu = wq - ktls_wq;
          if (bootverbose)
                  printf("Starting KTLS worker thread for CPU %d\n", cpu);
  
          /*
           * Bind to a core.  If ktls_bind_threads is > 1, then
           * we bind to the NUMA domain instead.
           */
          if (ktls_bind_threads) {
                  int error;
  
                  if (ktls_bind_threads > 1) {
                          struct pcpu *pc = pcpu_find(cpu);
  
                          error = ktls_bind_domain(pc->pc_domain);
                  } else {
                          cpuset_t mask;
  
                          CPU_SETOF(cpu, &mask);
                          error = cpuset_setthread(curthread->td_tid, &mask);
                  }
                  if (error)
                          printf("Unable to bind KTLS worker thread for CPU %d: error %d\n",
                                  cpu, error);
          }
  #if defined(__aarch64__) || defined(__amd64__) || defined(__i386__)
          fpu_kern_thread(0);
  #endif
          for (;;) {
                  mtx_lock(&wq->mtx);
                  while (STAILQ_EMPTY(&wq->m_head) &&
                      STAILQ_EMPTY(&wq->so_head)) {
                          wq->running = false;
                          mtx_sleep(wq, &wq->mtx, 0, "-", 0);
                          wq->running = true;
                  }
  
                  STAILQ_INIT(&local_m_head);
                  STAILQ_CONCAT(&local_m_head, &wq->m_head);
                  STAILQ_INIT(&local_so_head);
                  STAILQ_CONCAT(&local_so_head, &wq->so_head);
                  mtx_unlock(&wq->mtx);
  
                  STAILQ_FOREACH_SAFE(m, &local_m_head, m_epg_stailq, n) {
                          if (m->m_epg_flags & EPG_FLAG_2FREE) {
                                  ktls_free(m->m_epg_tls);
                                  m_free_raw(m);
                          } else {
                                  if (m->m_epg_tls->sync_dispatch)
                                          ktls_encrypt(wq, m);
                                  else
                                          ktls_encrypt_async(wq, m);
                                  counter_u64_add(ktls_cnt_tx_queued, -1);
                          }
                  }
  
                  STAILQ_FOREACH_SAFE(so, &local_so_head, so_ktls_rx_list, son) {
                          ktls_decrypt(so);
                          counter_u64_add(ktls_cnt_rx_queued, -1);
                  }
          }
  }
  
  #if defined(INET) || defined(INET6)
  static void
  ktls_disable_ifnet_help(void *context, int pending __unused)
  {
          struct ktls_session *tls;
          struct inpcb *inp;
          struct tcpcb *tp;
          struct socket *so;
          int err;
  
          tls = context;
          inp = tls->inp;
          if (inp == NULL)
                  return;
          INP_WLOCK(inp);
          so = inp->inp_socket;
          MPASS(so != NULL);
          if (inp->inp_flags & INP_DROPPED) {
                  goto out;
          }
  
          if (so->so_snd.sb_tls_info != NULL)
                  err = ktls_set_tx_mode(so, TCP_TLS_MODE_SW);
          else
                  err = ENXIO;
          if (err == 0) {
                  counter_u64_add(ktls_ifnet_disable_ok, 1);
                  /* ktls_set_tx_mode() drops inp wlock, so recheck flags */
                  if ((inp->inp_flags & INP_DROPPED) == 0 &&
                      (tp = intotcpcb(inp)) != NULL &&
                      tp->t_fb->tfb_hwtls_change != NULL)
                          (*tp->t_fb->tfb_hwtls_change)(tp, 0);
          } else {
                  counter_u64_add(ktls_ifnet_disable_fail, 1);
          }
  
  out:
          CURVNET_SET(so->so_vnet);
          sorele(so);
          CURVNET_RESTORE();
          if (!in_pcbrele_wlocked(inp))
                  INP_WUNLOCK(inp);
          ktls_free(tls);
  }
  
  /*
   * Called when re-transmits are becoming a substantial portion of the
   * sends on this connection.  When this happens, we transition the
   * connection to software TLS.  This is needed because most inline TLS
   * NICs keep crypto state only for in-order transmits.  This means
   * that to handle a TCP rexmit (which is out-of-order), the NIC must
   * re-DMA the entire TLS record up to and including the current
   * segment.  This means that when re-transmitting the last ~1448 byte
   * segment of a 16KB TLS record, we could wind up re-DMA'ing an order
   * of magnitude more data than we are sending.  This can cause the
   * PCIe link to saturate well before the network, which can cause
   * output drops, and a general loss of capacity.
   */
  void
  ktls_disable_ifnet(void *arg)
  {
          struct tcpcb *tp;
          struct inpcb *inp;
          struct socket *so;
          struct ktls_session *tls;
  
          tp = arg;
          inp = tptoinpcb(tp);
          INP_WLOCK_ASSERT(inp);
          so = inp->inp_socket;
          SOCK_LOCK(so);
          tls = so->so_snd.sb_tls_info;
          if (tls->disable_ifnet_pending) {
                  SOCK_UNLOCK(so);
                  return;
          }
  
          /*
           * note that disable_ifnet_pending is never cleared; disabling
           * ifnet can only be done once per session, so we never want
           * to do it again
           */
  
          (void)ktls_hold(tls);
          in_pcbref(inp);
          soref(so);
          tls->disable_ifnet_pending = true;
          tls->inp = inp;
          SOCK_UNLOCK(so);
          TASK_INIT(&tls->disable_ifnet_task, 0, ktls_disable_ifnet_help, tls);
          (void)taskqueue_enqueue(taskqueue_thread, &tls->disable_ifnet_task);
  }
  #endif

Cache object: 2a55c81a3770c8ba196ff34fb9fd48fc