The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/netinet/siftr.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2007-2009
    5  *      Swinburne University of Technology, Melbourne, Australia.
    6  * Copyright (c) 2009-2010, The FreeBSD Foundation
    7  * All rights reserved.
    8  *
    9  * Portions of this software were developed at the Centre for Advanced
   10  * Internet Architectures, Swinburne University of Technology, Melbourne,
   11  * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  */
   34 
   35 /******************************************************
   36  * Statistical Information For TCP Research (SIFTR)
   37  *
   38  * A FreeBSD kernel module that adds very basic intrumentation to the
   39  * TCP stack, allowing internal stats to be recorded to a log file
   40  * for experimental, debugging and performance analysis purposes.
   41  *
   42  * SIFTR was first released in 2007 by James Healy and Lawrence Stewart whilst
   43  * working on the NewTCP research project at Swinburne University of
   44  * Technology's Centre for Advanced Internet Architectures, Melbourne,
   45  * Australia, which was made possible in part by a grant from the Cisco
   46  * University Research Program Fund at Community Foundation Silicon Valley.
   47  * More details are available at:
   48  *   http://caia.swin.edu.au/urp/newtcp/
   49  *
   50  * Work on SIFTR v1.2.x was sponsored by the FreeBSD Foundation as part of
   51  * the "Enhancing the FreeBSD TCP Implementation" project 2008-2009.
   52  * More details are available at:
   53  *   http://www.freebsdfoundation.org/
   54  *   http://caia.swin.edu.au/freebsd/etcp09/
   55  *
   56  * Lawrence Stewart is the current maintainer, and all contact regarding
   57  * SIFTR should be directed to him via email: lastewart@swin.edu.au
   58  *
   59  * Initial release date: June 2007
   60  * Most recent update: September 2010
   61  ******************************************************/
   62 
   63 #include <sys/cdefs.h>
   64 __FBSDID("$FreeBSD$");
   65 
   66 #include <sys/param.h>
   67 #include <sys/alq.h>
   68 #include <sys/errno.h>
   69 #include <sys/eventhandler.h>
   70 #include <sys/hash.h>
   71 #include <sys/kernel.h>
   72 #include <sys/kthread.h>
   73 #include <sys/lock.h>
   74 #include <sys/mbuf.h>
   75 #include <sys/module.h>
   76 #include <sys/mutex.h>
   77 #include <sys/pcpu.h>
   78 #include <sys/proc.h>
   79 #include <sys/sbuf.h>
   80 #include <sys/sdt.h>
   81 #include <sys/smp.h>
   82 #include <sys/socket.h>
   83 #include <sys/socketvar.h>
   84 #include <sys/sysctl.h>
   85 #include <sys/unistd.h>
   86 
   87 #include <net/if.h>
   88 #include <net/if_var.h>
   89 #include <net/pfil.h>
   90 
   91 #include <netinet/in.h>
   92 #include <netinet/in_kdtrace.h>
   93 #include <netinet/in_pcb.h>
   94 #include <netinet/in_systm.h>
   95 #include <netinet/in_var.h>
   96 #include <netinet/ip.h>
   97 #include <netinet/ip_var.h>
   98 #include <netinet/tcp_var.h>
   99 
  100 #ifdef SIFTR_IPV6
  101 #include <netinet/ip6.h>
  102 #include <netinet6/ip6_var.h>
  103 #include <netinet6/in6_pcb.h>
  104 #endif /* SIFTR_IPV6 */
  105 
  106 #include <machine/in_cksum.h>
  107 
  108 /*
  109  * Three digit version number refers to X.Y.Z where:
  110  * X is the major version number
  111  * Y is bumped to mark backwards incompatible changes
  112  * Z is bumped to mark backwards compatible changes
  113  */
  114 #define V_MAJOR         1
  115 #define V_BACKBREAK     2
  116 #define V_BACKCOMPAT    4
  117 #define MODVERSION      __CONCAT(V_MAJOR, __CONCAT(V_BACKBREAK, V_BACKCOMPAT))
  118 #define MODVERSION_STR  __XSTRING(V_MAJOR) "." __XSTRING(V_BACKBREAK) "." \
  119     __XSTRING(V_BACKCOMPAT)
  120 
  121 #define HOOK 0
  122 #define UNHOOK 1
  123 #define SIFTR_EXPECTED_MAX_TCP_FLOWS 65536
  124 #define SYS_NAME "FreeBSD"
  125 #define PACKET_TAG_SIFTR 100
  126 #define PACKET_COOKIE_SIFTR 21749576
  127 #define SIFTR_LOG_FILE_MODE 0644
  128 #define SIFTR_DISABLE 0
  129 #define SIFTR_ENABLE 1
  130 
  131 /*
  132  * Hard upper limit on the length of log messages. Bump this up if you add new
  133  * data fields such that the line length could exceed the below value.
  134  */
  135 #define MAX_LOG_MSG_LEN 300
  136 /* XXX: Make this a sysctl tunable. */
  137 #define SIFTR_ALQ_BUFLEN (1000*MAX_LOG_MSG_LEN)
  138 
  139 /*
  140  * 1 byte for IP version
  141  * IPv4: src/dst IP (4+4) + src/dst port (2+2) = 12 bytes
  142  * IPv6: src/dst IP (16+16) + src/dst port (2+2) = 36 bytes
  143  */
  144 #ifdef SIFTR_IPV6
  145 #define FLOW_KEY_LEN 37
  146 #else
  147 #define FLOW_KEY_LEN 13
  148 #endif
  149 
  150 #ifdef SIFTR_IPV6
  151 #define SIFTR_IPMODE 6
  152 #else
  153 #define SIFTR_IPMODE 4
  154 #endif
  155 
  156 /* useful macros */
  157 #define UPPER_SHORT(X)  (((X) & 0xFFFF0000) >> 16)
  158 #define LOWER_SHORT(X)  ((X) & 0x0000FFFF)
  159 
  160 #define FIRST_OCTET(X)  (((X) & 0xFF000000) >> 24)
  161 #define SECOND_OCTET(X) (((X) & 0x00FF0000) >> 16)
  162 #define THIRD_OCTET(X)  (((X) & 0x0000FF00) >> 8)
  163 #define FOURTH_OCTET(X) ((X) & 0x000000FF)
  164 
  165 static MALLOC_DEFINE(M_SIFTR, "siftr", "dynamic memory used by SIFTR");
  166 static MALLOC_DEFINE(M_SIFTR_PKTNODE, "siftr_pktnode",
  167     "SIFTR pkt_node struct");
  168 static MALLOC_DEFINE(M_SIFTR_HASHNODE, "siftr_hashnode",
  169     "SIFTR flow_hash_node struct");
  170 
  171 /* Used as links in the pkt manager queue. */
  172 struct pkt_node {
  173         /* Timestamp of pkt as noted in the pfil hook. */
  174         struct timeval          tval;
  175         /* Direction pkt is travelling. */
  176         enum {
  177                 DIR_IN = 0,
  178                 DIR_OUT = 1,
  179         }                       direction;
  180         /* IP version pkt_node relates to; either INP_IPV4 or INP_IPV6. */
  181         uint8_t                 ipver;
  182         /* Hash of the pkt which triggered the log message. */
  183         uint32_t                hash;
  184         /* Local/foreign IP address. */
  185 #ifdef SIFTR_IPV6
  186         uint32_t                ip_laddr[4];
  187         uint32_t                ip_faddr[4];
  188 #else
  189         uint8_t                 ip_laddr[4];
  190         uint8_t                 ip_faddr[4];
  191 #endif
  192         /* Local TCP port. */
  193         uint16_t                tcp_localport;
  194         /* Foreign TCP port. */
  195         uint16_t                tcp_foreignport;
  196         /* Congestion Window (bytes). */
  197         uint32_t                snd_cwnd;
  198         /* Sending Window (bytes). */
  199         uint32_t                snd_wnd;
  200         /* Receive Window (bytes). */
  201         uint32_t                rcv_wnd;
  202         /* More tcpcb flags storage */
  203         uint32_t                t_flags2;
  204         /* Slow Start Threshold (bytes). */
  205         uint32_t                snd_ssthresh;
  206         /* Current state of the TCP FSM. */
  207         int                     conn_state;
  208         /* Max Segment Size (bytes). */
  209         u_int                   max_seg_size;
  210         /*
  211          * Smoothed RTT stored as found in the TCP control block
  212          * in units of (TCP_RTT_SCALE*hz).
  213          */
  214         int                     smoothed_rtt;
  215         /* Is SACK enabled? */
  216         u_char                  sack_enabled;
  217         /* Window scaling for snd window. */
  218         u_char                  snd_scale;
  219         /* Window scaling for recv window. */
  220         u_char                  rcv_scale;
  221         /* TCP control block flags. */
  222         u_int                   flags;
  223         /* Retransmit timeout length. */
  224         int                     rxt_length;
  225         /* Size of the TCP send buffer in bytes. */
  226         u_int                   snd_buf_hiwater;
  227         /* Current num bytes in the send socket buffer. */
  228         u_int                   snd_buf_cc;
  229         /* Size of the TCP receive buffer in bytes. */
  230         u_int                   rcv_buf_hiwater;
  231         /* Current num bytes in the receive socket buffer. */
  232         u_int                   rcv_buf_cc;
  233         /* Number of bytes inflight that we are waiting on ACKs for. */
  234         u_int                   sent_inflight_bytes;
  235         /* Number of segments currently in the reassembly queue. */
  236         int                     t_segqlen;
  237         /* Flowid for the connection. */
  238         u_int                   flowid;
  239         /* Flow type for the connection. */
  240         u_int                   flowtype;
  241         /* Link to next pkt_node in the list. */
  242         STAILQ_ENTRY(pkt_node)  nodes;
  243 };
  244 
  245 struct flow_hash_node
  246 {
  247         uint16_t counter;
  248         uint8_t key[FLOW_KEY_LEN];
  249         LIST_ENTRY(flow_hash_node) nodes;
  250 };
  251 
  252 struct siftr_stats
  253 {
  254         /* # TCP pkts seen by the SIFTR PFIL hooks, including any skipped. */
  255         uint64_t n_in;
  256         uint64_t n_out;
  257         /* # pkts skipped due to failed malloc calls. */
  258         uint32_t nskip_in_malloc;
  259         uint32_t nskip_out_malloc;
  260         /* # pkts skipped due to failed mtx acquisition. */
  261         uint32_t nskip_in_mtx;
  262         uint32_t nskip_out_mtx;
  263         /* # pkts skipped due to failed inpcb lookups. */
  264         uint32_t nskip_in_inpcb;
  265         uint32_t nskip_out_inpcb;
  266         /* # pkts skipped due to failed tcpcb lookups. */
  267         uint32_t nskip_in_tcpcb;
  268         uint32_t nskip_out_tcpcb;
  269         /* # pkts skipped due to stack reinjection. */
  270         uint32_t nskip_in_dejavu;
  271         uint32_t nskip_out_dejavu;
  272 };
  273 
  274 DPCPU_DEFINE_STATIC(struct siftr_stats, ss);
  275 
  276 static volatile unsigned int siftr_exit_pkt_manager_thread = 0;
  277 static unsigned int siftr_enabled = 0;
  278 static unsigned int siftr_pkts_per_log = 1;
  279 static unsigned int siftr_generate_hashes = 0;
  280 static uint16_t     siftr_port_filter = 0;
  281 /* static unsigned int siftr_binary_log = 0; */
  282 static char siftr_logfile[PATH_MAX] = "/var/log/siftr.log";
  283 static char siftr_logfile_shadow[PATH_MAX] = "/var/log/siftr.log";
  284 static u_long siftr_hashmask;
  285 STAILQ_HEAD(pkthead, pkt_node) pkt_queue = STAILQ_HEAD_INITIALIZER(pkt_queue);
  286 LIST_HEAD(listhead, flow_hash_node) *counter_hash;
  287 static int wait_for_pkt;
  288 static struct alq *siftr_alq = NULL;
  289 static struct mtx siftr_pkt_queue_mtx;
  290 static struct mtx siftr_pkt_mgr_mtx;
  291 static struct thread *siftr_pkt_manager_thr = NULL;
  292 static char direction[2] = {'i','o'};
  293 
  294 /* Required function prototypes. */
  295 static int siftr_sysctl_enabled_handler(SYSCTL_HANDLER_ARGS);
  296 static int siftr_sysctl_logfile_name_handler(SYSCTL_HANDLER_ARGS);
  297 
  298 /* Declare the net.inet.siftr sysctl tree and populate it. */
  299 
  300 SYSCTL_DECL(_net_inet_siftr);
  301 
  302 SYSCTL_NODE(_net_inet, OID_AUTO, siftr, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
  303     "siftr related settings");
  304 
  305 SYSCTL_PROC(_net_inet_siftr, OID_AUTO, enabled,
  306     CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
  307     &siftr_enabled, 0, &siftr_sysctl_enabled_handler, "IU",
  308     "switch siftr module operations on/off");
  309 
  310 SYSCTL_PROC(_net_inet_siftr, OID_AUTO, logfile,
  311     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_NEEDGIANT, &siftr_logfile_shadow,
  312     sizeof(siftr_logfile_shadow), &siftr_sysctl_logfile_name_handler, "A",
  313     "file to save siftr log messages to");
  314 
  315 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, ppl, CTLFLAG_RW,
  316     &siftr_pkts_per_log, 1,
  317     "number of packets between generating a log message");
  318 
  319 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, genhashes, CTLFLAG_RW,
  320     &siftr_generate_hashes, 0,
  321     "enable packet hash generation");
  322 
  323 SYSCTL_U16(_net_inet_siftr, OID_AUTO, port_filter, CTLFLAG_RW,
  324     &siftr_port_filter, 0,
  325     "enable packet filter on a TCP port");
  326 
  327 /* XXX: TODO
  328 SYSCTL_UINT(_net_inet_siftr, OID_AUTO, binary, CTLFLAG_RW,
  329     &siftr_binary_log, 0,
  330     "write log files in binary instead of ascii");
  331 */
  332 
  333 /* Begin functions. */
  334 
  335 static void
  336 siftr_process_pkt(struct pkt_node * pkt_node)
  337 {
  338         struct flow_hash_node *hash_node;
  339         struct listhead *counter_list;
  340         struct siftr_stats *ss;
  341         struct ale *log_buf;
  342         uint8_t key[FLOW_KEY_LEN];
  343         uint8_t found_match, key_offset;
  344 
  345         hash_node = NULL;
  346         ss = DPCPU_PTR(ss);
  347         found_match = 0;
  348         key_offset = 1;
  349 
  350         /*
  351          * Create the key that will be used to create a hash index
  352          * into our hash table. Our key consists of:
  353          * ipversion, localip, localport, foreignip, foreignport
  354          */
  355         key[0] = pkt_node->ipver;
  356         memcpy(key + key_offset, &pkt_node->ip_laddr,
  357             sizeof(pkt_node->ip_laddr));
  358         key_offset += sizeof(pkt_node->ip_laddr);
  359         memcpy(key + key_offset, &pkt_node->tcp_localport,
  360             sizeof(pkt_node->tcp_localport));
  361         key_offset += sizeof(pkt_node->tcp_localport);
  362         memcpy(key + key_offset, &pkt_node->ip_faddr,
  363             sizeof(pkt_node->ip_faddr));
  364         key_offset += sizeof(pkt_node->ip_faddr);
  365         memcpy(key + key_offset, &pkt_node->tcp_foreignport,
  366             sizeof(pkt_node->tcp_foreignport));
  367 
  368         counter_list = counter_hash +
  369             (hash32_buf(key, sizeof(key), 0) & siftr_hashmask);
  370 
  371         /*
  372          * If the list is not empty i.e. the hash index has
  373          * been used by another flow previously.
  374          */
  375         if (LIST_FIRST(counter_list) != NULL) {
  376                 /*
  377                  * Loop through the hash nodes in the list.
  378                  * There should normally only be 1 hash node in the list,
  379                  * except if there have been collisions at the hash index
  380                  * computed by hash32_buf().
  381                  */
  382                 LIST_FOREACH(hash_node, counter_list, nodes) {
  383                         /*
  384                          * Check if the key for the pkt we are currently
  385                          * processing is the same as the key stored in the
  386                          * hash node we are currently processing.
  387                          * If they are the same, then we've found the
  388                          * hash node that stores the counter for the flow
  389                          * the pkt belongs to.
  390                          */
  391                         if (memcmp(hash_node->key, key, sizeof(key)) == 0) {
  392                                 found_match = 1;
  393                                 break;
  394                         }
  395                 }
  396         }
  397 
  398         /* If this flow hash hasn't been seen before or we have a collision. */
  399         if (hash_node == NULL || !found_match) {
  400                 /* Create a new hash node to store the flow's counter. */
  401                 hash_node = malloc(sizeof(struct flow_hash_node),
  402                     M_SIFTR_HASHNODE, M_WAITOK);
  403 
  404                 if (hash_node != NULL) {
  405                         /* Initialise our new hash node list entry. */
  406                         hash_node->counter = 0;
  407                         memcpy(hash_node->key, key, sizeof(key));
  408                         LIST_INSERT_HEAD(counter_list, hash_node, nodes);
  409                 } else {
  410                         /* Malloc failed. */
  411                         if (pkt_node->direction == DIR_IN)
  412                                 ss->nskip_in_malloc++;
  413                         else
  414                                 ss->nskip_out_malloc++;
  415 
  416                         return;
  417                 }
  418         } else if (siftr_pkts_per_log > 1) {
  419                 /*
  420                  * Taking the remainder of the counter divided
  421                  * by the current value of siftr_pkts_per_log
  422                  * and storing that in counter provides a neat
  423                  * way to modulate the frequency of log
  424                  * messages being written to the log file.
  425                  */
  426                 hash_node->counter = (hash_node->counter + 1) %
  427                     siftr_pkts_per_log;
  428 
  429                 /*
  430                  * If we have not seen enough packets since the last time
  431                  * we wrote a log message for this connection, return.
  432                  */
  433                 if (hash_node->counter > 0)
  434                         return;
  435         }
  436 
  437         log_buf = alq_getn(siftr_alq, MAX_LOG_MSG_LEN, ALQ_WAITOK);
  438 
  439         if (log_buf == NULL)
  440                 return; /* Should only happen if the ALQ is shutting down. */
  441 
  442 #ifdef SIFTR_IPV6
  443         pkt_node->ip_laddr[3] = ntohl(pkt_node->ip_laddr[3]);
  444         pkt_node->ip_faddr[3] = ntohl(pkt_node->ip_faddr[3]);
  445 
  446         if (pkt_node->ipver == INP_IPV6) { /* IPv6 packet */
  447                 pkt_node->ip_laddr[0] = ntohl(pkt_node->ip_laddr[0]);
  448                 pkt_node->ip_laddr[1] = ntohl(pkt_node->ip_laddr[1]);
  449                 pkt_node->ip_laddr[2] = ntohl(pkt_node->ip_laddr[2]);
  450                 pkt_node->ip_faddr[0] = ntohl(pkt_node->ip_faddr[0]);
  451                 pkt_node->ip_faddr[1] = ntohl(pkt_node->ip_faddr[1]);
  452                 pkt_node->ip_faddr[2] = ntohl(pkt_node->ip_faddr[2]);
  453 
  454                 /* Construct an IPv6 log message. */
  455                 log_buf->ae_bytesused = snprintf(log_buf->ae_data,
  456                     MAX_LOG_MSG_LEN,
  457                     "%c,0x%08x,%zd.%06ld,%x:%x:%x:%x:%x:%x:%x:%x,%u,%x:%x:%x:"
  458                     "%x:%x:%x:%x:%x,%u,%u,%u,%u,%u,%u,%u,%u,%u,%u,%u,%u,"
  459                     "%u,%d,%u,%u,%u,%u,%u,%u,%u,%u\n",
  460                     direction[pkt_node->direction],
  461                     pkt_node->hash,
  462                     pkt_node->tval.tv_sec,
  463                     pkt_node->tval.tv_usec,
  464                     UPPER_SHORT(pkt_node->ip_laddr[0]),
  465                     LOWER_SHORT(pkt_node->ip_laddr[0]),
  466                     UPPER_SHORT(pkt_node->ip_laddr[1]),
  467                     LOWER_SHORT(pkt_node->ip_laddr[1]),
  468                     UPPER_SHORT(pkt_node->ip_laddr[2]),
  469                     LOWER_SHORT(pkt_node->ip_laddr[2]),
  470                     UPPER_SHORT(pkt_node->ip_laddr[3]),
  471                     LOWER_SHORT(pkt_node->ip_laddr[3]),
  472                     ntohs(pkt_node->tcp_localport),
  473                     UPPER_SHORT(pkt_node->ip_faddr[0]),
  474                     LOWER_SHORT(pkt_node->ip_faddr[0]),
  475                     UPPER_SHORT(pkt_node->ip_faddr[1]),
  476                     LOWER_SHORT(pkt_node->ip_faddr[1]),
  477                     UPPER_SHORT(pkt_node->ip_faddr[2]),
  478                     LOWER_SHORT(pkt_node->ip_faddr[2]),
  479                     UPPER_SHORT(pkt_node->ip_faddr[3]),
  480                     LOWER_SHORT(pkt_node->ip_faddr[3]),
  481                     ntohs(pkt_node->tcp_foreignport),
  482                     pkt_node->snd_ssthresh,
  483                     pkt_node->snd_cwnd,
  484                     pkt_node->t_flags2,
  485                     pkt_node->snd_wnd,
  486                     pkt_node->rcv_wnd,
  487                     pkt_node->snd_scale,
  488                     pkt_node->rcv_scale,
  489                     pkt_node->conn_state,
  490                     pkt_node->max_seg_size,
  491                     pkt_node->smoothed_rtt,
  492                     pkt_node->sack_enabled,
  493                     pkt_node->flags,
  494                     pkt_node->rxt_length,
  495                     pkt_node->snd_buf_hiwater,
  496                     pkt_node->snd_buf_cc,
  497                     pkt_node->rcv_buf_hiwater,
  498                     pkt_node->rcv_buf_cc,
  499                     pkt_node->sent_inflight_bytes,
  500                     pkt_node->t_segqlen,
  501                     pkt_node->flowid,
  502                     pkt_node->flowtype);
  503         } else { /* IPv4 packet */
  504                 pkt_node->ip_laddr[0] = FIRST_OCTET(pkt_node->ip_laddr[3]);
  505                 pkt_node->ip_laddr[1] = SECOND_OCTET(pkt_node->ip_laddr[3]);
  506                 pkt_node->ip_laddr[2] = THIRD_OCTET(pkt_node->ip_laddr[3]);
  507                 pkt_node->ip_laddr[3] = FOURTH_OCTET(pkt_node->ip_laddr[3]);
  508                 pkt_node->ip_faddr[0] = FIRST_OCTET(pkt_node->ip_faddr[3]);
  509                 pkt_node->ip_faddr[1] = SECOND_OCTET(pkt_node->ip_faddr[3]);
  510                 pkt_node->ip_faddr[2] = THIRD_OCTET(pkt_node->ip_faddr[3]);
  511                 pkt_node->ip_faddr[3] = FOURTH_OCTET(pkt_node->ip_faddr[3]);
  512 #endif /* SIFTR_IPV6 */
  513 
  514                 /* Construct an IPv4 log message. */
  515                 log_buf->ae_bytesused = snprintf(log_buf->ae_data,
  516                     MAX_LOG_MSG_LEN,
  517                     "%c,0x%08x,%jd.%06ld,%u.%u.%u.%u,%u,%u.%u.%u.%u,%u,%u,%u,"
  518                     "%u,%u,%u,%u,%u,%u,%u,%u,%u,%u,%d,%u,%u,%u,%u,%u,%u,%u,%u\n",
  519                     direction[pkt_node->direction],
  520                     pkt_node->hash,
  521                     (intmax_t)pkt_node->tval.tv_sec,
  522                     pkt_node->tval.tv_usec,
  523                     pkt_node->ip_laddr[0],
  524                     pkt_node->ip_laddr[1],
  525                     pkt_node->ip_laddr[2],
  526                     pkt_node->ip_laddr[3],
  527                     ntohs(pkt_node->tcp_localport),
  528                     pkt_node->ip_faddr[0],
  529                     pkt_node->ip_faddr[1],
  530                     pkt_node->ip_faddr[2],
  531                     pkt_node->ip_faddr[3],
  532                     ntohs(pkt_node->tcp_foreignport),
  533                     pkt_node->snd_ssthresh,
  534                     pkt_node->snd_cwnd,
  535                     pkt_node->t_flags2,
  536                     pkt_node->snd_wnd,
  537                     pkt_node->rcv_wnd,
  538                     pkt_node->snd_scale,
  539                     pkt_node->rcv_scale,
  540                     pkt_node->conn_state,
  541                     pkt_node->max_seg_size,
  542                     pkt_node->smoothed_rtt,
  543                     pkt_node->sack_enabled,
  544                     pkt_node->flags,
  545                     pkt_node->rxt_length,
  546                     pkt_node->snd_buf_hiwater,
  547                     pkt_node->snd_buf_cc,
  548                     pkt_node->rcv_buf_hiwater,
  549                     pkt_node->rcv_buf_cc,
  550                     pkt_node->sent_inflight_bytes,
  551                     pkt_node->t_segqlen,
  552                     pkt_node->flowid,
  553                     pkt_node->flowtype);
  554 #ifdef SIFTR_IPV6
  555         }
  556 #endif
  557 
  558         alq_post_flags(siftr_alq, log_buf, 0);
  559 }
  560 
  561 static void
  562 siftr_pkt_manager_thread(void *arg)
  563 {
  564         STAILQ_HEAD(pkthead, pkt_node) tmp_pkt_queue =
  565             STAILQ_HEAD_INITIALIZER(tmp_pkt_queue);
  566         struct pkt_node *pkt_node, *pkt_node_temp;
  567         uint8_t draining;
  568 
  569         draining = 2;
  570 
  571         mtx_lock(&siftr_pkt_mgr_mtx);
  572 
  573         /* draining == 0 when queue has been flushed and it's safe to exit. */
  574         while (draining) {
  575                 /*
  576                  * Sleep until we are signalled to wake because thread has
  577                  * been told to exit or until 1 tick has passed.
  578                  */
  579                 mtx_sleep(&wait_for_pkt, &siftr_pkt_mgr_mtx, PWAIT, "pktwait",
  580                     1);
  581 
  582                 /* Gain exclusive access to the pkt_node queue. */
  583                 mtx_lock(&siftr_pkt_queue_mtx);
  584 
  585                 /*
  586                  * Move pkt_queue to tmp_pkt_queue, which leaves
  587                  * pkt_queue empty and ready to receive more pkt_nodes.
  588                  */
  589                 STAILQ_CONCAT(&tmp_pkt_queue, &pkt_queue);
  590 
  591                 /*
  592                  * We've finished making changes to the list. Unlock it
  593                  * so the pfil hooks can continue queuing pkt_nodes.
  594                  */
  595                 mtx_unlock(&siftr_pkt_queue_mtx);
  596 
  597                 /*
  598                  * We can't hold a mutex whilst calling siftr_process_pkt
  599                  * because ALQ might sleep waiting for buffer space.
  600                  */
  601                 mtx_unlock(&siftr_pkt_mgr_mtx);
  602 
  603                 /* Flush all pkt_nodes to the log file. */
  604                 STAILQ_FOREACH_SAFE(pkt_node, &tmp_pkt_queue, nodes,
  605                     pkt_node_temp) {
  606                         siftr_process_pkt(pkt_node);
  607                         STAILQ_REMOVE_HEAD(&tmp_pkt_queue, nodes);
  608                         free(pkt_node, M_SIFTR_PKTNODE);
  609                 }
  610 
  611                 KASSERT(STAILQ_EMPTY(&tmp_pkt_queue),
  612                     ("SIFTR tmp_pkt_queue not empty after flush"));
  613 
  614                 mtx_lock(&siftr_pkt_mgr_mtx);
  615 
  616                 /*
  617                  * If siftr_exit_pkt_manager_thread gets set during the window
  618                  * where we are draining the tmp_pkt_queue above, there might
  619                  * still be pkts in pkt_queue that need to be drained.
  620                  * Allow one further iteration to occur after
  621                  * siftr_exit_pkt_manager_thread has been set to ensure
  622                  * pkt_queue is completely empty before we kill the thread.
  623                  *
  624                  * siftr_exit_pkt_manager_thread is set only after the pfil
  625                  * hooks have been removed, so only 1 extra iteration
  626                  * is needed to drain the queue.
  627                  */
  628                 if (siftr_exit_pkt_manager_thread)
  629                         draining--;
  630         }
  631 
  632         mtx_unlock(&siftr_pkt_mgr_mtx);
  633 
  634         /* Calls wakeup on this thread's struct thread ptr. */
  635         kthread_exit();
  636 }
  637 
  638 static uint32_t
  639 hash_pkt(struct mbuf *m, uint32_t offset)
  640 {
  641         uint32_t hash;
  642 
  643         hash = 0;
  644 
  645         while (m != NULL && offset > m->m_len) {
  646                 /*
  647                  * The IP packet payload does not start in this mbuf, so
  648                  * need to figure out which mbuf it starts in and what offset
  649                  * into the mbuf's data region the payload starts at.
  650                  */
  651                 offset -= m->m_len;
  652                 m = m->m_next;
  653         }
  654 
  655         while (m != NULL) {
  656                 /* Ensure there is data in the mbuf */
  657                 if ((m->m_len - offset) > 0)
  658                         hash = hash32_buf(m->m_data + offset,
  659                             m->m_len - offset, hash);
  660 
  661                 m = m->m_next;
  662                 offset = 0;
  663         }
  664 
  665         return (hash);
  666 }
  667 
  668 /*
  669  * Check if a given mbuf has the SIFTR mbuf tag. If it does, log the fact that
  670  * it's a reinjected packet and return. If it doesn't, tag the mbuf and return.
  671  * Return value >0 means the caller should skip processing this mbuf.
  672  */
  673 static inline int
  674 siftr_chkreinject(struct mbuf *m, int dir, struct siftr_stats *ss)
  675 {
  676         if (m_tag_locate(m, PACKET_COOKIE_SIFTR, PACKET_TAG_SIFTR, NULL)
  677             != NULL) {
  678                 if (dir == PFIL_IN)
  679                         ss->nskip_in_dejavu++;
  680                 else
  681                         ss->nskip_out_dejavu++;
  682 
  683                 return (1);
  684         } else {
  685                 struct m_tag *tag = m_tag_alloc(PACKET_COOKIE_SIFTR,
  686                     PACKET_TAG_SIFTR, 0, M_NOWAIT);
  687                 if (tag == NULL) {
  688                         if (dir == PFIL_IN)
  689                                 ss->nskip_in_malloc++;
  690                         else
  691                                 ss->nskip_out_malloc++;
  692 
  693                         return (1);
  694                 }
  695 
  696                 m_tag_prepend(m, tag);
  697         }
  698 
  699         return (0);
  700 }
  701 
  702 /*
  703  * Look up an inpcb for a packet. Return the inpcb pointer if found, or NULL
  704  * otherwise.
  705  */
  706 static inline struct inpcb *
  707 siftr_findinpcb(int ipver, struct ip *ip, struct mbuf *m, uint16_t sport,
  708     uint16_t dport, int dir, struct siftr_stats *ss)
  709 {
  710         struct inpcb *inp;
  711 
  712         /* We need the tcbinfo lock. */
  713         INP_INFO_WUNLOCK_ASSERT(&V_tcbinfo);
  714 
  715         if (dir == PFIL_IN)
  716                 inp = (ipver == INP_IPV4 ?
  717                     in_pcblookup(&V_tcbinfo, ip->ip_src, sport, ip->ip_dst,
  718                     dport, INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif)
  719                     :
  720 #ifdef SIFTR_IPV6
  721                     in6_pcblookup(&V_tcbinfo,
  722                     &((struct ip6_hdr *)ip)->ip6_src, sport,
  723                     &((struct ip6_hdr *)ip)->ip6_dst, dport, INPLOOKUP_RLOCKPCB,
  724                     m->m_pkthdr.rcvif)
  725 #else
  726                     NULL
  727 #endif
  728                     );
  729 
  730         else
  731                 inp = (ipver == INP_IPV4 ?
  732                     in_pcblookup(&V_tcbinfo, ip->ip_dst, dport, ip->ip_src,
  733                     sport, INPLOOKUP_RLOCKPCB, m->m_pkthdr.rcvif)
  734                     :
  735 #ifdef SIFTR_IPV6
  736                     in6_pcblookup(&V_tcbinfo,
  737                     &((struct ip6_hdr *)ip)->ip6_dst, dport,
  738                     &((struct ip6_hdr *)ip)->ip6_src, sport, INPLOOKUP_RLOCKPCB,
  739                     m->m_pkthdr.rcvif)
  740 #else
  741                     NULL
  742 #endif
  743                     );
  744 
  745         /* If we can't find the inpcb, bail. */
  746         if (inp == NULL) {
  747                 if (dir == PFIL_IN)
  748                         ss->nskip_in_inpcb++;
  749                 else
  750                         ss->nskip_out_inpcb++;
  751         }
  752 
  753         return (inp);
  754 }
  755 
  756 static inline void
  757 siftr_siftdata(struct pkt_node *pn, struct inpcb *inp, struct tcpcb *tp,
  758     int ipver, int dir, int inp_locally_locked)
  759 {
  760 #ifdef SIFTR_IPV6
  761         if (ipver == INP_IPV4) {
  762                 pn->ip_laddr[3] = inp->inp_laddr.s_addr;
  763                 pn->ip_faddr[3] = inp->inp_faddr.s_addr;
  764 #else
  765                 *((uint32_t *)pn->ip_laddr) = inp->inp_laddr.s_addr;
  766                 *((uint32_t *)pn->ip_faddr) = inp->inp_faddr.s_addr;
  767 #endif
  768 #ifdef SIFTR_IPV6
  769         } else {
  770                 pn->ip_laddr[0] = inp->in6p_laddr.s6_addr32[0];
  771                 pn->ip_laddr[1] = inp->in6p_laddr.s6_addr32[1];
  772                 pn->ip_laddr[2] = inp->in6p_laddr.s6_addr32[2];
  773                 pn->ip_laddr[3] = inp->in6p_laddr.s6_addr32[3];
  774                 pn->ip_faddr[0] = inp->in6p_faddr.s6_addr32[0];
  775                 pn->ip_faddr[1] = inp->in6p_faddr.s6_addr32[1];
  776                 pn->ip_faddr[2] = inp->in6p_faddr.s6_addr32[2];
  777                 pn->ip_faddr[3] = inp->in6p_faddr.s6_addr32[3];
  778         }
  779 #endif
  780         pn->tcp_localport = inp->inp_lport;
  781         pn->tcp_foreignport = inp->inp_fport;
  782         pn->snd_cwnd = tp->snd_cwnd;
  783         pn->snd_wnd = tp->snd_wnd;
  784         pn->rcv_wnd = tp->rcv_wnd;
  785         pn->t_flags2 = tp->t_flags2;
  786         pn->snd_ssthresh = tp->snd_ssthresh;
  787         pn->snd_scale = tp->snd_scale;
  788         pn->rcv_scale = tp->rcv_scale;
  789         pn->conn_state = tp->t_state;
  790         pn->max_seg_size = tp->t_maxseg;
  791         pn->smoothed_rtt = tp->t_srtt;
  792         pn->sack_enabled = (tp->t_flags & TF_SACK_PERMIT) != 0;
  793         pn->flags = tp->t_flags;
  794         pn->rxt_length = tp->t_rxtcur;
  795         pn->snd_buf_hiwater = inp->inp_socket->so_snd.sb_hiwat;
  796         pn->snd_buf_cc = sbused(&inp->inp_socket->so_snd);
  797         pn->rcv_buf_hiwater = inp->inp_socket->so_rcv.sb_hiwat;
  798         pn->rcv_buf_cc = sbused(&inp->inp_socket->so_rcv);
  799         pn->sent_inflight_bytes = tp->snd_max - tp->snd_una;
  800         pn->t_segqlen = tp->t_segqlen;
  801         pn->flowid = inp->inp_flowid;
  802         pn->flowtype = inp->inp_flowtype;
  803 
  804         /* We've finished accessing the tcb so release the lock. */
  805         if (inp_locally_locked)
  806                 INP_RUNLOCK(inp);
  807 
  808         pn->ipver = ipver;
  809         pn->direction = (dir == PFIL_IN ? DIR_IN : DIR_OUT);
  810 
  811         /*
  812          * Significantly more accurate than using getmicrotime(), but slower!
  813          * Gives true microsecond resolution at the expense of a hit to
  814          * maximum pps throughput processing when SIFTR is loaded and enabled.
  815          */
  816         microtime(&pn->tval);
  817         TCP_PROBE1(siftr, &pn);
  818 
  819 }
  820 
  821 /*
  822  * pfil hook that is called for each IPv4 packet making its way through the
  823  * stack in either direction.
  824  * The pfil subsystem holds a non-sleepable mutex somewhere when
  825  * calling our hook function, so we can't sleep at all.
  826  * It's very important to use the M_NOWAIT flag with all function calls
  827  * that support it so that they won't sleep, otherwise you get a panic.
  828  */
  829 static pfil_return_t
  830 siftr_chkpkt(struct mbuf **m, struct ifnet *ifp, int flags,
  831     void *ruleset __unused, struct inpcb *inp)
  832 {
  833         struct pkt_node *pn;
  834         struct ip *ip;
  835         struct tcphdr *th;
  836         struct tcpcb *tp;
  837         struct siftr_stats *ss;
  838         unsigned int ip_hl;
  839         int inp_locally_locked, dir;
  840 
  841         inp_locally_locked = 0;
  842         dir = PFIL_DIR(flags);
  843         ss = DPCPU_PTR(ss);
  844 
  845         /*
  846          * m_pullup is not required here because ip_{input|output}
  847          * already do the heavy lifting for us.
  848          */
  849 
  850         ip = mtod(*m, struct ip *);
  851 
  852         /* Only continue processing if the packet is TCP. */
  853         if (ip->ip_p != IPPROTO_TCP)
  854                 goto ret;
  855 
  856         /*
  857          * Create a tcphdr struct starting at the correct offset
  858          * in the IP packet. ip->ip_hl gives the ip header length
  859          * in 4-byte words, so multiply it to get the size in bytes.
  860          */
  861         ip_hl = (ip->ip_hl << 2);
  862         th = (struct tcphdr *)((caddr_t)ip + ip_hl);
  863 
  864         /*
  865          * Only pkts selected by the tcp port filter
  866          * can be inserted into the pkt_queue
  867          */
  868         if ((siftr_port_filter != 0) &&
  869             (siftr_port_filter != ntohs(th->th_sport)) &&
  870             (siftr_port_filter != ntohs(th->th_dport))) {
  871                 goto ret;
  872         }
  873 
  874         /*
  875          * If a kernel subsystem reinjects packets into the stack, our pfil
  876          * hook will be called multiple times for the same packet.
  877          * Make sure we only process unique packets.
  878          */
  879         if (siftr_chkreinject(*m, dir, ss))
  880                 goto ret;
  881 
  882         if (dir == PFIL_IN)
  883                 ss->n_in++;
  884         else
  885                 ss->n_out++;
  886 
  887         /*
  888          * If the pfil hooks don't provide a pointer to the
  889          * inpcb, we need to find it ourselves and lock it.
  890          */
  891         if (!inp) {
  892                 /* Find the corresponding inpcb for this pkt. */
  893                 inp = siftr_findinpcb(INP_IPV4, ip, *m, th->th_sport,
  894                     th->th_dport, dir, ss);
  895 
  896                 if (inp == NULL)
  897                         goto ret;
  898                 else
  899                         inp_locally_locked = 1;
  900         }
  901 
  902         INP_LOCK_ASSERT(inp);
  903 
  904         /* Find the TCP control block that corresponds with this packet */
  905         tp = intotcpcb(inp);
  906 
  907         /*
  908          * If we can't find the TCP control block (happens occasionaly for a
  909          * packet sent during the shutdown phase of a TCP connection), bail
  910          */
  911         if (tp == NULL) {
  912                 if (dir == PFIL_IN)
  913                         ss->nskip_in_tcpcb++;
  914                 else
  915                         ss->nskip_out_tcpcb++;
  916 
  917                 goto inp_unlock;
  918         }
  919 
  920 
  921         pn = malloc(sizeof(struct pkt_node), M_SIFTR_PKTNODE, M_NOWAIT|M_ZERO);
  922 
  923         if (pn == NULL) {
  924                 if (dir == PFIL_IN)
  925                         ss->nskip_in_malloc++;
  926                 else
  927                         ss->nskip_out_malloc++;
  928 
  929                 goto inp_unlock;
  930         }
  931 
  932         siftr_siftdata(pn, inp, tp, INP_IPV4, dir, inp_locally_locked);
  933 
  934         if (siftr_generate_hashes) {
  935                 if ((*m)->m_pkthdr.csum_flags & CSUM_TCP) {
  936                         /*
  937                          * For outbound packets, the TCP checksum isn't
  938                          * calculated yet. This is a problem for our packet
  939                          * hashing as the receiver will calc a different hash
  940                          * to ours if we don't include the correct TCP checksum
  941                          * in the bytes being hashed. To work around this
  942                          * problem, we manually calc the TCP checksum here in
  943                          * software. We unset the CSUM_TCP flag so the lower
  944                          * layers don't recalc it.
  945                          */
  946                         (*m)->m_pkthdr.csum_flags &= ~CSUM_TCP;
  947 
  948                         /*
  949                          * Calculate the TCP checksum in software and assign
  950                          * to correct TCP header field, which will follow the
  951                          * packet mbuf down the stack. The trick here is that
  952                          * tcp_output() sets th->th_sum to the checksum of the
  953                          * pseudo header for us already. Because of the nature
  954                          * of the checksumming algorithm, we can sum over the
  955                          * entire IP payload (i.e. TCP header and data), which
  956                          * will include the already calculated pseduo header
  957                          * checksum, thus giving us the complete TCP checksum.
  958                          *
  959                          * To put it in simple terms, if checksum(1,2,3,4)=10,
  960                          * then checksum(1,2,3,4,5) == checksum(10,5).
  961                          * This property is what allows us to "cheat" and
  962                          * checksum only the IP payload which has the TCP
  963                          * th_sum field populated with the pseudo header's
  964                          * checksum, and not need to futz around checksumming
  965                          * pseudo header bytes and TCP header/data in one hit.
  966                          * Refer to RFC 1071 for more info.
  967                          *
  968                          * NB: in_cksum_skip(struct mbuf *m, int len, int skip)
  969                          * in_cksum_skip 2nd argument is NOT the number of
  970                          * bytes to read from the mbuf at "skip" bytes offset
  971                          * from the start of the mbuf (very counter intuitive!).
  972                          * The number of bytes to read is calculated internally
  973                          * by the function as len-skip i.e. to sum over the IP
  974                          * payload (TCP header + data) bytes, it is INCORRECT
  975                          * to call the function like this:
  976                          * in_cksum_skip(at, ip->ip_len - offset, offset)
  977                          * Rather, it should be called like this:
  978                          * in_cksum_skip(at, ip->ip_len, offset)
  979                          * which means read "ip->ip_len - offset" bytes from
  980                          * the mbuf cluster "at" at offset "offset" bytes from
  981                          * the beginning of the "at" mbuf's data pointer.
  982                          */
  983                         th->th_sum = in_cksum_skip(*m, ntohs(ip->ip_len),
  984                             ip_hl);
  985                 }
  986 
  987                 /*
  988                  * XXX: Having to calculate the checksum in software and then
  989                  * hash over all bytes is really inefficient. Would be nice to
  990                  * find a way to create the hash and checksum in the same pass
  991                  * over the bytes.
  992                  */
  993                 pn->hash = hash_pkt(*m, ip_hl);
  994         }
  995 
  996         mtx_lock(&siftr_pkt_queue_mtx);
  997         STAILQ_INSERT_TAIL(&pkt_queue, pn, nodes);
  998         mtx_unlock(&siftr_pkt_queue_mtx);
  999         goto ret;
 1000 
 1001 inp_unlock:
 1002         if (inp_locally_locked)
 1003                 INP_RUNLOCK(inp);
 1004 
 1005 ret:
 1006         return (PFIL_PASS);
 1007 }
 1008 
 1009 #ifdef SIFTR_IPV6
 1010 static pfil_return_t
 1011 siftr_chkpkt6(struct mbuf **m, struct ifnet *ifp, int flags,
 1012     void *ruleset __unused, struct inpcb *inp)
 1013 {
 1014         struct pkt_node *pn;
 1015         struct ip6_hdr *ip6;
 1016         struct tcphdr *th;
 1017         struct tcpcb *tp;
 1018         struct siftr_stats *ss;
 1019         unsigned int ip6_hl;
 1020         int inp_locally_locked, dir;
 1021 
 1022         inp_locally_locked = 0;
 1023         dir = PFIL_DIR(flags);
 1024         ss = DPCPU_PTR(ss);
 1025 
 1026         /*
 1027          * m_pullup is not required here because ip6_{input|output}
 1028          * already do the heavy lifting for us.
 1029          */
 1030 
 1031         ip6 = mtod(*m, struct ip6_hdr *);
 1032 
 1033         /*
 1034          * Only continue processing if the packet is TCP
 1035          * XXX: We should follow the next header fields
 1036          * as shown on Pg 6 RFC 2460, but right now we'll
 1037          * only check pkts that have no extension headers.
 1038          */
 1039         if (ip6->ip6_nxt != IPPROTO_TCP)
 1040                 goto ret6;
 1041 
 1042         /*
 1043          * Create a tcphdr struct starting at the correct offset
 1044          * in the ipv6 packet.
 1045          */
 1046         ip6_hl = sizeof(struct ip6_hdr);
 1047         th = (struct tcphdr *)((caddr_t)ip6 + ip6_hl);
 1048 
 1049         /*
 1050          * Only pkts selected by the tcp port filter
 1051          * can be inserted into the pkt_queue
 1052          */
 1053         if ((siftr_port_filter != 0) &&
 1054             (siftr_port_filter != ntohs(th->th_sport)) &&
 1055             (siftr_port_filter != ntohs(th->th_dport))) {
 1056                 goto ret6;
 1057         }
 1058 
 1059         /*
 1060          * If a kernel subsystem reinjects packets into the stack, our pfil
 1061          * hook will be called multiple times for the same packet.
 1062          * Make sure we only process unique packets.
 1063          */
 1064         if (siftr_chkreinject(*m, dir, ss))
 1065                 goto ret6;
 1066 
 1067         if (dir == PFIL_IN)
 1068                 ss->n_in++;
 1069         else
 1070                 ss->n_out++;
 1071 
 1072         /*
 1073          * For inbound packets, the pfil hooks don't provide a pointer to the
 1074          * inpcb, so we need to find it ourselves and lock it.
 1075          */
 1076         if (!inp) {
 1077                 /* Find the corresponding inpcb for this pkt. */
 1078                 inp = siftr_findinpcb(INP_IPV6, (struct ip *)ip6, *m,
 1079                     th->th_sport, th->th_dport, dir, ss);
 1080 
 1081                 if (inp == NULL)
 1082                         goto ret6;
 1083                 else
 1084                         inp_locally_locked = 1;
 1085         }
 1086 
 1087         /* Find the TCP control block that corresponds with this packet. */
 1088         tp = intotcpcb(inp);
 1089 
 1090         /*
 1091          * If we can't find the TCP control block (happens occasionaly for a
 1092          * packet sent during the shutdown phase of a TCP connection), bail
 1093          */
 1094         if (tp == NULL) {
 1095                 if (dir == PFIL_IN)
 1096                         ss->nskip_in_tcpcb++;
 1097                 else
 1098                         ss->nskip_out_tcpcb++;
 1099 
 1100                 goto inp_unlock6;
 1101         }
 1102 
 1103 
 1104         pn = malloc(sizeof(struct pkt_node), M_SIFTR_PKTNODE, M_NOWAIT|M_ZERO);
 1105 
 1106         if (pn == NULL) {
 1107                 if (dir == PFIL_IN)
 1108                         ss->nskip_in_malloc++;
 1109                 else
 1110                         ss->nskip_out_malloc++;
 1111 
 1112                 goto inp_unlock6;
 1113         }
 1114 
 1115         siftr_siftdata(pn, inp, tp, INP_IPV6, dir, inp_locally_locked);
 1116 
 1117         /* XXX: Figure out how to generate hashes for IPv6 packets. */
 1118 
 1119         mtx_lock(&siftr_pkt_queue_mtx);
 1120         STAILQ_INSERT_TAIL(&pkt_queue, pn, nodes);
 1121         mtx_unlock(&siftr_pkt_queue_mtx);
 1122         goto ret6;
 1123 
 1124 inp_unlock6:
 1125         if (inp_locally_locked)
 1126                 INP_RUNLOCK(inp);
 1127 
 1128 ret6:
 1129         return (PFIL_PASS);
 1130 }
 1131 #endif /* #ifdef SIFTR_IPV6 */
 1132 
 1133 VNET_DEFINE_STATIC(pfil_hook_t, siftr_inet_hook);
 1134 #define V_siftr_inet_hook       VNET(siftr_inet_hook)
 1135 #ifdef SIFTR_IPV6
 1136 VNET_DEFINE_STATIC(pfil_hook_t, siftr_inet6_hook);
 1137 #define V_siftr_inet6_hook      VNET(siftr_inet6_hook)
 1138 #endif
 1139 static int
 1140 siftr_pfil(int action)
 1141 {
 1142         struct pfil_hook_args pha;
 1143         struct pfil_link_args pla;
 1144 
 1145         pha.pa_version = PFIL_VERSION;
 1146         pha.pa_flags = PFIL_IN | PFIL_OUT;
 1147         pha.pa_modname = "siftr";
 1148         pha.pa_ruleset = NULL;
 1149         pha.pa_rulname = "default";
 1150 
 1151         pla.pa_version = PFIL_VERSION;
 1152         pla.pa_flags = PFIL_IN | PFIL_OUT |
 1153             PFIL_HEADPTR | PFIL_HOOKPTR;
 1154 
 1155         VNET_ITERATOR_DECL(vnet_iter);
 1156 
 1157         VNET_LIST_RLOCK();
 1158         VNET_FOREACH(vnet_iter) {
 1159                 CURVNET_SET(vnet_iter);
 1160 
 1161                 if (action == HOOK) {
 1162                         pha.pa_func = siftr_chkpkt;
 1163                         pha.pa_type = PFIL_TYPE_IP4;
 1164                         V_siftr_inet_hook = pfil_add_hook(&pha);
 1165                         pla.pa_hook = V_siftr_inet_hook;
 1166                         pla.pa_head = V_inet_pfil_head;
 1167                         (void)pfil_link(&pla);
 1168 #ifdef SIFTR_IPV6
 1169                         pha.pa_func = siftr_chkpkt6;
 1170                         pha.pa_type = PFIL_TYPE_IP6;
 1171                         V_siftr_inet6_hook = pfil_add_hook(&pha);
 1172                         pla.pa_hook = V_siftr_inet6_hook;
 1173                         pla.pa_head = V_inet6_pfil_head;
 1174                         (void)pfil_link(&pla);
 1175 #endif
 1176                 } else if (action == UNHOOK) {
 1177                         pfil_remove_hook(V_siftr_inet_hook);
 1178 #ifdef SIFTR_IPV6
 1179                         pfil_remove_hook(V_siftr_inet6_hook);
 1180 #endif
 1181                 }
 1182                 CURVNET_RESTORE();
 1183         }
 1184         VNET_LIST_RUNLOCK();
 1185 
 1186         return (0);
 1187 }
 1188 
 1189 static int
 1190 siftr_sysctl_logfile_name_handler(SYSCTL_HANDLER_ARGS)
 1191 {
 1192         struct alq *new_alq;
 1193         int error;
 1194 
 1195         error = sysctl_handle_string(oidp, arg1, arg2, req);
 1196 
 1197         /* Check for error or same filename */
 1198         if (error != 0 || req->newptr == NULL ||
 1199             strncmp(siftr_logfile, arg1, arg2) == 0)
 1200                 goto done;
 1201 
 1202         /* Filname changed */
 1203         error = alq_open(&new_alq, arg1, curthread->td_ucred,
 1204             SIFTR_LOG_FILE_MODE, SIFTR_ALQ_BUFLEN, 0);
 1205         if (error != 0)
 1206                 goto done;
 1207 
 1208         /*
 1209          * If disabled, siftr_alq == NULL so we simply close
 1210          * the alq as we've proved it can be opened.
 1211          * If enabled, close the existing alq and switch the old
 1212          * for the new.
 1213          */
 1214         if (siftr_alq == NULL) {
 1215                 alq_close(new_alq);
 1216         } else {
 1217                 alq_close(siftr_alq);
 1218                 siftr_alq = new_alq;
 1219         }
 1220 
 1221         /* Update filename upon success */
 1222         strlcpy(siftr_logfile, arg1, arg2);
 1223 done:
 1224         return (error);
 1225 }
 1226 
 1227 static int
 1228 siftr_manage_ops(uint8_t action)
 1229 {
 1230         struct siftr_stats totalss;
 1231         struct timeval tval;
 1232         struct flow_hash_node *counter, *tmp_counter;
 1233         struct sbuf *s;
 1234         int i, key_index, error;
 1235         uint32_t bytes_to_write, total_skipped_pkts;
 1236         uint16_t lport, fport;
 1237         uint8_t *key, ipver __unused;
 1238 
 1239 #ifdef SIFTR_IPV6
 1240         uint32_t laddr[4];
 1241         uint32_t faddr[4];
 1242 #else
 1243         uint8_t laddr[4];
 1244         uint8_t faddr[4];
 1245 #endif
 1246 
 1247         error = 0;
 1248         total_skipped_pkts = 0;
 1249 
 1250         /* Init an autosizing sbuf that initially holds 200 chars. */
 1251         if ((s = sbuf_new(NULL, NULL, 200, SBUF_AUTOEXTEND)) == NULL)
 1252                 return (-1);
 1253 
 1254         if (action == SIFTR_ENABLE && siftr_pkt_manager_thr == NULL) {
 1255                 /*
 1256                  * Create our alq
 1257                  * XXX: We should abort if alq_open fails!
 1258                  */
 1259                 alq_open(&siftr_alq, siftr_logfile, curthread->td_ucred,
 1260                     SIFTR_LOG_FILE_MODE, SIFTR_ALQ_BUFLEN, 0);
 1261 
 1262                 STAILQ_INIT(&pkt_queue);
 1263 
 1264                 DPCPU_ZERO(ss);
 1265 
 1266                 siftr_exit_pkt_manager_thread = 0;
 1267 
 1268                 kthread_add(&siftr_pkt_manager_thread, NULL, NULL,
 1269                     &siftr_pkt_manager_thr, RFNOWAIT, 0,
 1270                     "siftr_pkt_manager_thr");
 1271 
 1272                 siftr_pfil(HOOK);
 1273 
 1274                 microtime(&tval);
 1275 
 1276                 sbuf_printf(s,
 1277                     "enable_time_secs=%jd\tenable_time_usecs=%06ld\t"
 1278                     "siftrver=%s\thz=%u\ttcp_rtt_scale=%u\tsysname=%s\t"
 1279                     "sysver=%u\tipmode=%u\n",
 1280                     (intmax_t)tval.tv_sec, tval.tv_usec, MODVERSION_STR, hz,
 1281                     TCP_RTT_SCALE, SYS_NAME, __FreeBSD_version, SIFTR_IPMODE);
 1282 
 1283                 sbuf_finish(s);
 1284                 alq_writen(siftr_alq, sbuf_data(s), sbuf_len(s), ALQ_WAITOK);
 1285 
 1286         } else if (action == SIFTR_DISABLE && siftr_pkt_manager_thr != NULL) {
 1287                 /*
 1288                  * Remove the pfil hook functions. All threads currently in
 1289                  * the hook functions are allowed to exit before siftr_pfil()
 1290                  * returns.
 1291                  */
 1292                 siftr_pfil(UNHOOK);
 1293 
 1294                 /* This will block until the pkt manager thread unlocks it. */
 1295                 mtx_lock(&siftr_pkt_mgr_mtx);
 1296 
 1297                 /* Tell the pkt manager thread that it should exit now. */
 1298                 siftr_exit_pkt_manager_thread = 1;
 1299 
 1300                 /*
 1301                  * Wake the pkt_manager thread so it realises that
 1302                  * siftr_exit_pkt_manager_thread == 1 and exits gracefully.
 1303                  * The wakeup won't be delivered until we unlock
 1304                  * siftr_pkt_mgr_mtx so this isn't racy.
 1305                  */
 1306                 wakeup(&wait_for_pkt);
 1307 
 1308                 /* Wait for the pkt_manager thread to exit. */
 1309                 mtx_sleep(siftr_pkt_manager_thr, &siftr_pkt_mgr_mtx, PWAIT,
 1310                     "thrwait", 0);
 1311 
 1312                 siftr_pkt_manager_thr = NULL;
 1313                 mtx_unlock(&siftr_pkt_mgr_mtx);
 1314 
 1315                 totalss.n_in = DPCPU_VARSUM(ss, n_in);
 1316                 totalss.n_out = DPCPU_VARSUM(ss, n_out);
 1317                 totalss.nskip_in_malloc = DPCPU_VARSUM(ss, nskip_in_malloc);
 1318                 totalss.nskip_out_malloc = DPCPU_VARSUM(ss, nskip_out_malloc);
 1319                 totalss.nskip_in_mtx = DPCPU_VARSUM(ss, nskip_in_mtx);
 1320                 totalss.nskip_out_mtx = DPCPU_VARSUM(ss, nskip_out_mtx);
 1321                 totalss.nskip_in_tcpcb = DPCPU_VARSUM(ss, nskip_in_tcpcb);
 1322                 totalss.nskip_out_tcpcb = DPCPU_VARSUM(ss, nskip_out_tcpcb);
 1323                 totalss.nskip_in_inpcb = DPCPU_VARSUM(ss, nskip_in_inpcb);
 1324                 totalss.nskip_out_inpcb = DPCPU_VARSUM(ss, nskip_out_inpcb);
 1325 
 1326                 total_skipped_pkts = totalss.nskip_in_malloc +
 1327                     totalss.nskip_out_malloc + totalss.nskip_in_mtx +
 1328                     totalss.nskip_out_mtx + totalss.nskip_in_tcpcb +
 1329                     totalss.nskip_out_tcpcb + totalss.nskip_in_inpcb +
 1330                     totalss.nskip_out_inpcb;
 1331 
 1332                 microtime(&tval);
 1333 
 1334                 sbuf_printf(s,
 1335                     "disable_time_secs=%jd\tdisable_time_usecs=%06ld\t"
 1336                     "num_inbound_tcp_pkts=%ju\tnum_outbound_tcp_pkts=%ju\t"
 1337                     "total_tcp_pkts=%ju\tnum_inbound_skipped_pkts_malloc=%u\t"
 1338                     "num_outbound_skipped_pkts_malloc=%u\t"
 1339                     "num_inbound_skipped_pkts_mtx=%u\t"
 1340                     "num_outbound_skipped_pkts_mtx=%u\t"
 1341                     "num_inbound_skipped_pkts_tcpcb=%u\t"
 1342                     "num_outbound_skipped_pkts_tcpcb=%u\t"
 1343                     "num_inbound_skipped_pkts_inpcb=%u\t"
 1344                     "num_outbound_skipped_pkts_inpcb=%u\t"
 1345                     "total_skipped_tcp_pkts=%u\tflow_list=",
 1346                     (intmax_t)tval.tv_sec,
 1347                     tval.tv_usec,
 1348                     (uintmax_t)totalss.n_in,
 1349                     (uintmax_t)totalss.n_out,
 1350                     (uintmax_t)(totalss.n_in + totalss.n_out),
 1351                     totalss.nskip_in_malloc,
 1352                     totalss.nskip_out_malloc,
 1353                     totalss.nskip_in_mtx,
 1354                     totalss.nskip_out_mtx,
 1355                     totalss.nskip_in_tcpcb,
 1356                     totalss.nskip_out_tcpcb,
 1357                     totalss.nskip_in_inpcb,
 1358                     totalss.nskip_out_inpcb,
 1359                     total_skipped_pkts);
 1360 
 1361                 /*
 1362                  * Iterate over the flow hash, printing a summary of each
 1363                  * flow seen and freeing any malloc'd memory.
 1364                  * The hash consists of an array of LISTs (man 3 queue).
 1365                  */
 1366                 for (i = 0; i <= siftr_hashmask; i++) {
 1367                         LIST_FOREACH_SAFE(counter, counter_hash + i, nodes,
 1368                             tmp_counter) {
 1369                                 key = counter->key;
 1370                                 key_index = 1;
 1371 
 1372                                 ipver = key[0];
 1373 
 1374                                 memcpy(laddr, key + key_index, sizeof(laddr));
 1375                                 key_index += sizeof(laddr);
 1376                                 memcpy(&lport, key + key_index, sizeof(lport));
 1377                                 key_index += sizeof(lport);
 1378                                 memcpy(faddr, key + key_index, sizeof(faddr));
 1379                                 key_index += sizeof(faddr);
 1380                                 memcpy(&fport, key + key_index, sizeof(fport));
 1381 
 1382 #ifdef SIFTR_IPV6
 1383                                 laddr[3] = ntohl(laddr[3]);
 1384                                 faddr[3] = ntohl(faddr[3]);
 1385 
 1386                                 if (ipver == INP_IPV6) {
 1387                                         laddr[0] = ntohl(laddr[0]);
 1388                                         laddr[1] = ntohl(laddr[1]);
 1389                                         laddr[2] = ntohl(laddr[2]);
 1390                                         faddr[0] = ntohl(faddr[0]);
 1391                                         faddr[1] = ntohl(faddr[1]);
 1392                                         faddr[2] = ntohl(faddr[2]);
 1393 
 1394                                         sbuf_printf(s,
 1395                                             "%x:%x:%x:%x:%x:%x:%x:%x;%u-"
 1396                                             "%x:%x:%x:%x:%x:%x:%x:%x;%u,",
 1397                                             UPPER_SHORT(laddr[0]),
 1398                                             LOWER_SHORT(laddr[0]),
 1399                                             UPPER_SHORT(laddr[1]),
 1400                                             LOWER_SHORT(laddr[1]),
 1401                                             UPPER_SHORT(laddr[2]),
 1402                                             LOWER_SHORT(laddr[2]),
 1403                                             UPPER_SHORT(laddr[3]),
 1404                                             LOWER_SHORT(laddr[3]),
 1405                                             ntohs(lport),
 1406                                             UPPER_SHORT(faddr[0]),
 1407                                             LOWER_SHORT(faddr[0]),
 1408                                             UPPER_SHORT(faddr[1]),
 1409                                             LOWER_SHORT(faddr[1]),
 1410                                             UPPER_SHORT(faddr[2]),
 1411                                             LOWER_SHORT(faddr[2]),
 1412                                             UPPER_SHORT(faddr[3]),
 1413                                             LOWER_SHORT(faddr[3]),
 1414                                             ntohs(fport));
 1415                                 } else {
 1416                                         laddr[0] = FIRST_OCTET(laddr[3]);
 1417                                         laddr[1] = SECOND_OCTET(laddr[3]);
 1418                                         laddr[2] = THIRD_OCTET(laddr[3]);
 1419                                         laddr[3] = FOURTH_OCTET(laddr[3]);
 1420                                         faddr[0] = FIRST_OCTET(faddr[3]);
 1421                                         faddr[1] = SECOND_OCTET(faddr[3]);
 1422                                         faddr[2] = THIRD_OCTET(faddr[3]);
 1423                                         faddr[3] = FOURTH_OCTET(faddr[3]);
 1424 #endif
 1425                                         sbuf_printf(s,
 1426                                             "%u.%u.%u.%u;%u-%u.%u.%u.%u;%u,",
 1427                                             laddr[0],
 1428                                             laddr[1],
 1429                                             laddr[2],
 1430                                             laddr[3],
 1431                                             ntohs(lport),
 1432                                             faddr[0],
 1433                                             faddr[1],
 1434                                             faddr[2],
 1435                                             faddr[3],
 1436                                             ntohs(fport));
 1437 #ifdef SIFTR_IPV6
 1438                                 }
 1439 #endif
 1440 
 1441                                 free(counter, M_SIFTR_HASHNODE);
 1442                         }
 1443 
 1444                         LIST_INIT(counter_hash + i);
 1445                 }
 1446 
 1447                 sbuf_printf(s, "\n");
 1448                 sbuf_finish(s);
 1449 
 1450                 i = 0;
 1451                 do {
 1452                         bytes_to_write = min(SIFTR_ALQ_BUFLEN, sbuf_len(s)-i);
 1453                         alq_writen(siftr_alq, sbuf_data(s)+i, bytes_to_write, ALQ_WAITOK);
 1454                         i += bytes_to_write;
 1455                 } while (i < sbuf_len(s));
 1456 
 1457                 alq_close(siftr_alq);
 1458                 siftr_alq = NULL;
 1459         } else
 1460                 error = EINVAL;
 1461 
 1462         sbuf_delete(s);
 1463 
 1464         /*
 1465          * XXX: Should be using ret to check if any functions fail
 1466          * and set error appropriately
 1467          */
 1468 
 1469         return (error);
 1470 }
 1471 
 1472 static int
 1473 siftr_sysctl_enabled_handler(SYSCTL_HANDLER_ARGS)
 1474 {
 1475         int error;
 1476         uint32_t new;
 1477 
 1478         new = siftr_enabled;
 1479         error = sysctl_handle_int(oidp, &new, 0, req);
 1480         if (error == 0 && req->newptr != NULL) {
 1481                 if (new > 1)
 1482                         return (EINVAL);
 1483                 else if (new != siftr_enabled) {
 1484                         if ((error = siftr_manage_ops(new)) == 0) {
 1485                                 siftr_enabled = new;
 1486                         } else {
 1487                                 siftr_manage_ops(SIFTR_DISABLE);
 1488                         }
 1489                 }
 1490         }
 1491 
 1492         return (error);
 1493 }
 1494 
 1495 static void
 1496 siftr_shutdown_handler(void *arg)
 1497 {
 1498         if (siftr_enabled == 1) {
 1499                 siftr_manage_ops(SIFTR_DISABLE);
 1500         }
 1501 }
 1502 
 1503 /*
 1504  * Module is being unloaded or machine is shutting down. Take care of cleanup.
 1505  */
 1506 static int
 1507 deinit_siftr(void)
 1508 {
 1509         /* Cleanup. */
 1510         siftr_manage_ops(SIFTR_DISABLE);
 1511         hashdestroy(counter_hash, M_SIFTR, siftr_hashmask);
 1512         mtx_destroy(&siftr_pkt_queue_mtx);
 1513         mtx_destroy(&siftr_pkt_mgr_mtx);
 1514 
 1515         return (0);
 1516 }
 1517 
 1518 /*
 1519  * Module has just been loaded into the kernel.
 1520  */
 1521 static int
 1522 init_siftr(void)
 1523 {
 1524         EVENTHANDLER_REGISTER(shutdown_pre_sync, siftr_shutdown_handler, NULL,
 1525             SHUTDOWN_PRI_FIRST);
 1526 
 1527         /* Initialise our flow counter hash table. */
 1528         counter_hash = hashinit(SIFTR_EXPECTED_MAX_TCP_FLOWS, M_SIFTR,
 1529             &siftr_hashmask);
 1530 
 1531         mtx_init(&siftr_pkt_queue_mtx, "siftr_pkt_queue_mtx", NULL, MTX_DEF);
 1532         mtx_init(&siftr_pkt_mgr_mtx, "siftr_pkt_mgr_mtx", NULL, MTX_DEF);
 1533 
 1534         /* Print message to the user's current terminal. */
 1535         uprintf("\nStatistical Information For TCP Research (SIFTR) %s\n"
 1536             "          http://caia.swin.edu.au/urp/newtcp\n\n",
 1537             MODVERSION_STR);
 1538 
 1539         return (0);
 1540 }
 1541 
 1542 /*
 1543  * This is the function that is called to load and unload the module.
 1544  * When the module is loaded, this function is called once with
 1545  * "what" == MOD_LOAD
 1546  * When the module is unloaded, this function is called twice with
 1547  * "what" = MOD_QUIESCE first, followed by "what" = MOD_UNLOAD second
 1548  * When the system is shut down e.g. CTRL-ALT-DEL or using the shutdown command,
 1549  * this function is called once with "what" = MOD_SHUTDOWN
 1550  * When the system is shut down, the handler isn't called until the very end
 1551  * of the shutdown sequence i.e. after the disks have been synced.
 1552  */
 1553 static int
 1554 siftr_load_handler(module_t mod, int what, void *arg)
 1555 {
 1556         int ret;
 1557 
 1558         switch (what) {
 1559         case MOD_LOAD:
 1560                 ret = init_siftr();
 1561                 break;
 1562 
 1563         case MOD_QUIESCE:
 1564         case MOD_SHUTDOWN:
 1565                 ret = deinit_siftr();
 1566                 break;
 1567 
 1568         case MOD_UNLOAD:
 1569                 ret = 0;
 1570                 break;
 1571 
 1572         default:
 1573                 ret = EINVAL;
 1574                 break;
 1575         }
 1576 
 1577         return (ret);
 1578 }
 1579 
 1580 static moduledata_t siftr_mod = {
 1581         .name = "siftr",
 1582         .evhand = siftr_load_handler,
 1583 };
 1584 
 1585 /*
 1586  * Param 1: name of the kernel module
 1587  * Param 2: moduledata_t struct containing info about the kernel module
 1588  *          and the execution entry point for the module
 1589  * Param 3: From sysinit_sub_id enumeration in /usr/include/sys/kernel.h
 1590  *          Defines the module initialisation order
 1591  * Param 4: From sysinit_elem_order enumeration in /usr/include/sys/kernel.h
 1592  *          Defines the initialisation order of this kld relative to others
 1593  *          within the same subsystem as defined by param 3
 1594  */
 1595 DECLARE_MODULE(siftr, siftr_mod, SI_SUB_LAST, SI_ORDER_ANY);
 1596 MODULE_DEPEND(siftr, alq, 1, 1, 1);
 1597 MODULE_VERSION(siftr, MODVERSION);

Cache object: bb0447e8e291c2e5dc9babd345a2d4a7


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