FreeBSD/Linux Kernel Cross Reference
sys/net/netmap_user.h

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (C) 2011-2016 Universita` di Pisa
      * All rights reserved.
      *
      * 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 AUTHOR 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.
     */
    
    /*
     * $FreeBSD: releng/12.0/sys/net/netmap_user.h 339906 2018-10-30 08:36:36Z vmaffione $
     *
     * Functions and macros to manipulate netmap structures and packets
     * in userspace. See netmap(4) for more information.
     *
     * The address of the struct netmap_if, say nifp, is computed from the
     * value returned from ioctl(.., NIOCREG, ...) and the mmap region:
     *      ioctl(fd, NIOCREG, &req);
     *      mem = mmap(0, ... );
     *      nifp = NETMAP_IF(mem, req.nr_nifp);
     *              (so simple, we could just do it manually)
     *
     * From there:
     *      struct netmap_ring *NETMAP_TXRING(nifp, index)
     *      struct netmap_ring *NETMAP_RXRING(nifp, index)
     *              we can access ring->cur, ring->head, ring->tail, etc.
     *
     *      ring->slot[i] gives us the i-th slot (we can access
     *              directly len, flags, buf_idx)
     *
     *      char *buf = NETMAP_BUF(ring, x) returns a pointer to
     *              the buffer numbered x
     *
     * All ring indexes (head, cur, tail) should always move forward.
     * To compute the next index in a circular ring you can use
     *      i = nm_ring_next(ring, i);
     *
     * To ease porting apps from pcap to netmap we supply a few fuctions
     * that can be called to open, close, read and write on netmap in a way
     * similar to libpcap. Note that the read/write function depend on
     * an ioctl()/select()/poll() being issued to refill rings or push
     * packets out.
     *
     * In order to use these, include #define NETMAP_WITH_LIBS
     * in the source file that invokes these functions.
     */
    
    #ifndef _NET_NETMAP_USER_H_
    #define _NET_NETMAP_USER_H_
    
    #define NETMAP_DEVICE_NAME "/dev/netmap"
    
    #ifdef __CYGWIN__
    /*
     * we can compile userspace apps with either cygwin or msvc,
     * and we use _WIN32 to identify windows specific code
     */
    #ifndef _WIN32
    #define _WIN32
    #endif  /* _WIN32 */
    
    #endif  /* __CYGWIN__ */
    
    #ifdef _WIN32
    #undef NETMAP_DEVICE_NAME
    #define NETMAP_DEVICE_NAME "/proc/sys/DosDevices/Global/netmap"
    #include <windows.h>
    #include <WinDef.h>
    #include <sys/cygwin.h>
    #endif /* _WIN32 */
    
    #include <stdint.h>
    #include <sys/socket.h>         /* apple needs sockaddr */
    #include <net/if.h>             /* IFNAMSIZ */
    #include <ctype.h>
    
    #ifndef likely
    #define likely(x)       __builtin_expect(!!(x), 1)
    #define unlikely(x)     __builtin_expect(!!(x), 0)
   #endif /* likely and unlikely */
   
   #include <net/netmap.h>
   
   /* helper macro */
   #define _NETMAP_OFFSET(type, ptr, offset) \
           ((type)(void *)((char *)(ptr) + (offset)))
   
   #define NETMAP_IF(_base, _ofs)  _NETMAP_OFFSET(struct netmap_if *, _base, _ofs)
   
   #define NETMAP_TXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \
           nifp, (nifp)->ring_ofs[index] )
   
   #define NETMAP_RXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \
           nifp, (nifp)->ring_ofs[index + (nifp)->ni_tx_rings + 1] )
   
   #define NETMAP_BUF(ring, index)                         \
           ((char *)(ring) + (ring)->buf_ofs + ((index)*(ring)->nr_buf_size))
   
   #define NETMAP_BUF_IDX(ring, buf)                       \
           ( ((char *)(buf) - ((char *)(ring) + (ring)->buf_ofs) ) / \
                   (ring)->nr_buf_size )
   
   
   static inline uint32_t
   nm_ring_next(struct netmap_ring *r, uint32_t i)
   {
           return ( unlikely(i + 1 == r->num_slots) ? 0 : i + 1);
   }
   
   
   /*
    * Return 1 if we have pending transmissions in the tx ring.
    * When everything is complete ring->head = ring->tail + 1 (modulo ring size)
    */
   static inline int
   nm_tx_pending(struct netmap_ring *r)
   {
           return nm_ring_next(r, r->tail) != r->head;
   }
   
   
   static inline uint32_t
   nm_ring_space(struct netmap_ring *ring)
   {
           int ret = ring->tail - ring->cur;
           if (ret < 0)
                   ret += ring->num_slots;
           return ret;
   }
   
   
   #ifdef NETMAP_WITH_LIBS
   /*
    * Support for simple I/O libraries.
    * Include other system headers required for compiling this.
    */
   
   #ifndef HAVE_NETMAP_WITH_LIBS
   #define HAVE_NETMAP_WITH_LIBS
   
   #include <stdio.h>
   #include <sys/time.h>
   #include <sys/mman.h>
   #include <string.h>     /* memset */
   #include <sys/ioctl.h>
   #include <sys/errno.h>  /* EINVAL */
   #include <fcntl.h>      /* O_RDWR */
   #include <unistd.h>     /* close() */
   #include <signal.h>
   #include <stdlib.h>
   
   #ifndef ND /* debug macros */
   /* debug support */
   #define ND(_fmt, ...) do {} while(0)
   #define D(_fmt, ...)                                            \
           do {                                                    \
                   struct timeval _t0;                             \
                   gettimeofday(&_t0, NULL);                       \
                   fprintf(stderr, "%03d.%06d %s [%d] " _fmt "\n", \
                       (int)(_t0.tv_sec % 1000), (int)_t0.tv_usec, \
                       __FUNCTION__, __LINE__, ##__VA_ARGS__);     \
           } while (0)
   
   /* Rate limited version of "D", lps indicates how many per second */
   #define RD(lps, format, ...)                                    \
       do {                                                        \
           static int __t0, __cnt;                                 \
           struct timeval __xxts;                                  \
           gettimeofday(&__xxts, NULL);                            \
           if (__t0 != __xxts.tv_sec) {                            \
               __t0 = __xxts.tv_sec;                               \
               __cnt = 0;                                          \
           }                                                       \
           if (__cnt++ < lps) {                                    \
               D(format, ##__VA_ARGS__);                           \
           }                                                       \
       } while (0)
   #endif
   
   struct nm_pkthdr {      /* first part is the same as pcap_pkthdr */
           struct timeval  ts;
           uint32_t        caplen;
           uint32_t        len;
   
           uint64_t flags; /* NM_MORE_PKTS etc */
   #define NM_MORE_PKTS    1
           struct nm_desc *d;
           struct netmap_slot *slot;
           uint8_t *buf;
   };
   
   struct nm_stat {        /* same as pcap_stat    */
           u_int   ps_recv;
           u_int   ps_drop;
           u_int   ps_ifdrop;
   #ifdef WIN32 /* XXX or _WIN32 ? */
           u_int   bs_capt;
   #endif /* WIN32 */
   };
   
   #define NM_ERRBUF_SIZE  512
   
   struct nm_desc {
           struct nm_desc *self; /* point to self if netmap. */
           int fd;
           void *mem;
           uint32_t memsize;
           int done_mmap;  /* set if mem is the result of mmap */
           struct netmap_if * const nifp;
           uint16_t first_tx_ring, last_tx_ring, cur_tx_ring;
           uint16_t first_rx_ring, last_rx_ring, cur_rx_ring;
           struct nmreq req;       /* also contains the nr_name = ifname */
           struct nm_pkthdr hdr;
   
           /*
            * The memory contains netmap_if, rings and then buffers.
            * Given a pointer (e.g. to nm_inject) we can compare with
            * mem/buf_start/buf_end to tell if it is a buffer or
            * some other descriptor in our region.
            * We also store a pointer to some ring as it helps in the
            * translation from buffer indexes to addresses.
            */
           struct netmap_ring * const some_ring;
           void * const buf_start;
           void * const buf_end;
           /* parameters from pcap_open_live */
           int snaplen;
           int promisc;
           int to_ms;
           char *errbuf;
   
           /* save flags so we can restore them on close */
           uint32_t if_flags;
           uint32_t if_reqcap;
           uint32_t if_curcap;
   
           struct nm_stat st;
           char msg[NM_ERRBUF_SIZE];
   };
   
   /*
    * when the descriptor is open correctly, d->self == d
    * Eventually we should also use some magic number.
    */
   #define P2NMD(p)                ((struct nm_desc *)(p))
   #define IS_NETMAP_DESC(d)       ((d) && P2NMD(d)->self == P2NMD(d))
   #define NETMAP_FD(d)            (P2NMD(d)->fd)
   
   
   /*
    * this is a slightly optimized copy routine which rounds
    * to multiple of 64 bytes and is often faster than dealing
    * with other odd sizes. We assume there is enough room
    * in the source and destination buffers.
    */
   static inline void
   nm_pkt_copy(const void *_src, void *_dst, int l)
   {
           const uint64_t *src = (const uint64_t *)_src;
           uint64_t *dst = (uint64_t *)_dst;
   
           if (unlikely(l >= 1024 || l % 64)) {
                   memcpy(dst, src, l);
                   return;
           }
           for (; likely(l > 0); l-=64) {
                   *dst++ = *src++;
                   *dst++ = *src++;
                   *dst++ = *src++;
                   *dst++ = *src++;
                   *dst++ = *src++;
                   *dst++ = *src++;
                   *dst++ = *src++;
                   *dst++ = *src++;
           }
   }
   
   
   /*
    * The callback, invoked on each received packet. Same as libpcap
    */
   typedef void (*nm_cb_t)(u_char *, const struct nm_pkthdr *, const u_char *d);
   
   /*
    *--- the pcap-like API ---
    *
    * nm_open() opens a file descriptor, binds to a port and maps memory.
    *
    * ifname       (netmap:foo or vale:foo) is the port name
    *              a suffix can indicate the follwing:
    *              ^               bind the host (sw) ring pair
    *              *               bind host and NIC ring pairs
    *              -NN             bind individual NIC ring pair
    *              {NN             bind master side of pipe NN
    *              }NN             bind slave side of pipe NN
    *              a suffix starting with / and the following flags,
    *              in any order:
    *              x               exclusive access
    *              z               zero copy monitor (both tx and rx)
    *              t               monitor tx side (copy monitor)
    *              r               monitor rx side (copy monitor)
    *              R               bind only RX ring(s)
    *              T               bind only TX ring(s)
    *
    * req          provides the initial values of nmreq before parsing ifname.
    *              Remember that the ifname parsing will override the ring
    *              number in nm_ringid, and part of nm_flags;
    * flags        special functions, normally 0
    *              indicates which fields of *arg are significant
    * arg          special functions, normally NULL
    *              if passed a netmap_desc with mem != NULL,
    *              use that memory instead of mmap.
    */
   
   static struct nm_desc *nm_open(const char *ifname, const struct nmreq *req,
           uint64_t flags, const struct nm_desc *arg);
   
   /*
    * nm_open can import some fields from the parent descriptor.
    * These flags control which ones.
    * Also in flags you can specify NETMAP_NO_TX_POLL and NETMAP_DO_RX_POLL,
    * which set the initial value for these flags.
    * Note that the 16 low bits of the flags are reserved for data
    * that may go into the nmreq.
    */
   enum {
           NM_OPEN_NO_MMAP =       0x040000, /* reuse mmap from parent */
           NM_OPEN_IFNAME =        0x080000, /* nr_name, nr_ringid, nr_flags */
           NM_OPEN_ARG1 =          0x100000,
           NM_OPEN_ARG2 =          0x200000,
           NM_OPEN_ARG3 =          0x400000,
           NM_OPEN_RING_CFG =      0x800000, /* tx|rx rings|slots */
   };
   
   
   /*
    * nm_close()   closes and restores the port to its previous state
    */
   
   static int nm_close(struct nm_desc *);
   
   /*
    * nm_mmap()    do mmap or inherit from parent if the nr_arg2
    *              (memory block) matches.
    */
   
   static int nm_mmap(struct nm_desc *, const struct nm_desc *);
   
   /*
    * nm_inject() is the same as pcap_inject()
    * nm_dispatch() is the same as pcap_dispatch()
    * nm_nextpkt() is the same as pcap_next()
    */
   
   static int nm_inject(struct nm_desc *, const void *, size_t);
   static int nm_dispatch(struct nm_desc *, int, nm_cb_t, u_char *);
   static u_char *nm_nextpkt(struct nm_desc *, struct nm_pkthdr *);
   
   #ifdef _WIN32
   
   intptr_t _get_osfhandle(int); /* defined in io.h in windows */
   
   /*
    * In windows we do not have yet native poll support, so we keep track
    * of file descriptors associated to netmap ports to emulate poll on
    * them and fall back on regular poll on other file descriptors.
    */
   struct win_netmap_fd_list {
           struct win_netmap_fd_list *next;
           int win_netmap_fd;
           HANDLE win_netmap_handle;
   };
   
   /*
    * list head containing all the netmap opened fd and their
    * windows HANDLE counterparts
    */
   static struct win_netmap_fd_list *win_netmap_fd_list_head;
   
   static void
   win_insert_fd_record(int fd)
   {
           struct win_netmap_fd_list *curr;
   
           for (curr = win_netmap_fd_list_head; curr; curr = curr->next) {
                   if (fd == curr->win_netmap_fd) {
                           return;
                   }
           }
           curr = calloc(1, sizeof(*curr));
           curr->next = win_netmap_fd_list_head;
           curr->win_netmap_fd = fd;
           curr->win_netmap_handle = IntToPtr(_get_osfhandle(fd));
           win_netmap_fd_list_head = curr;
   }
   
   void
   win_remove_fd_record(int fd)
   {
           struct win_netmap_fd_list *curr = win_netmap_fd_list_head;
           struct win_netmap_fd_list *prev = NULL;
           for (; curr ; prev = curr, curr = curr->next) {
                   if (fd != curr->win_netmap_fd)
                           continue;
                   /* found the entry */
                   if (prev == NULL) { /* we are freeing the first entry */
                           win_netmap_fd_list_head = curr->next;
                   } else {
                           prev->next = curr->next;
                   }
                   free(curr);
                   break;
           }
   }
   
   
   HANDLE
   win_get_netmap_handle(int fd)
   {
           struct win_netmap_fd_list *curr;
   
           for (curr = win_netmap_fd_list_head; curr; curr = curr->next) {
                   if (fd == curr->win_netmap_fd) {
                           return curr->win_netmap_handle;
                   }
           }
           return NULL;
   }
   
   /*
    * we need to wrap ioctl and mmap, at least for the netmap file descriptors
    */
   
   /*
    * use this function only from netmap_user.h internal functions
    * same as ioctl, returns 0 on success and -1 on error
    */
   static int
   win_nm_ioctl_internal(HANDLE h, int32_t ctlCode, void *arg)
   {
           DWORD bReturn = 0, szIn, szOut;
           BOOL ioctlReturnStatus;
           void *inParam = arg, *outParam = arg;
   
           switch (ctlCode) {
           case NETMAP_POLL:
                   szIn = sizeof(POLL_REQUEST_DATA);
                   szOut = sizeof(POLL_REQUEST_DATA);
                   break;
           case NETMAP_MMAP:
                   szIn = 0;
                   szOut = sizeof(void*);
                   inParam = NULL; /* nothing on input */
                   break;
           case NIOCTXSYNC:
           case NIOCRXSYNC:
                   szIn = 0;
                   szOut = 0;
                   break;
           case NIOCREGIF:
                   szIn = sizeof(struct nmreq);
                   szOut = sizeof(struct nmreq);
                   break;
           case NIOCCONFIG:
                   D("unsupported NIOCCONFIG!");
                   return -1;
   
           default: /* a regular ioctl */
                   D("invalid ioctl %x on netmap fd", ctlCode);
                   return -1;
           }
   
           ioctlReturnStatus = DeviceIoControl(h,
                                   ctlCode, inParam, szIn,
                                   outParam, szOut,
                                   &bReturn, NULL);
           // XXX note windows returns 0 on error or async call, 1 on success
           // we could call GetLastError() to figure out what happened
           return ioctlReturnStatus ? 0 : -1;
   }
   
   /*
    * this function is what must be called from user-space programs
    * same as ioctl, returns 0 on success and -1 on error
    */
   static int
   win_nm_ioctl(int fd, int32_t ctlCode, void *arg)
   {
           HANDLE h = win_get_netmap_handle(fd);
   
           if (h == NULL) {
                   return ioctl(fd, ctlCode, arg);
           } else {
                   return win_nm_ioctl_internal(h, ctlCode, arg);
           }
   }
   
   #define ioctl win_nm_ioctl /* from now on, within this file ... */
   
   /*
    * We cannot use the native mmap on windows
    * The only parameter used is "fd", the other ones are just declared to
    * make this signature comparable to the FreeBSD/Linux one
    */
   static void *
   win32_mmap_emulated(void *addr, size_t length, int prot, int flags, int fd, int32_t offset)
   {
           HANDLE h = win_get_netmap_handle(fd);
   
           if (h == NULL) {
                   return mmap(addr, length, prot, flags, fd, offset);
           } else {
                   MEMORY_ENTRY ret;
   
                   return win_nm_ioctl_internal(h, NETMAP_MMAP, &ret) ?
                           NULL : ret.pUsermodeVirtualAddress;
           }
   }
   
   #define mmap win32_mmap_emulated
   
   #include <sys/poll.h> /* XXX needed to use the structure pollfd */
   
   static int
   win_nm_poll(struct pollfd *fds, int nfds, int timeout)
   {
           HANDLE h;
   
           if (nfds != 1 || fds == NULL || (h = win_get_netmap_handle(fds->fd)) == NULL) {;
                   return poll(fds, nfds, timeout);
           } else {
                   POLL_REQUEST_DATA prd;
   
                   prd.timeout = timeout;
                   prd.events = fds->events;
   
                   win_nm_ioctl_internal(h, NETMAP_POLL, &prd);
                   if ((prd.revents == POLLERR) || (prd.revents == STATUS_TIMEOUT)) {
                           return -1;
                   }
                   return 1;
           }
   }
   
   #define poll win_nm_poll
   
   static int
   win_nm_open(char* pathname, int flags)
   {
   
           if (strcmp(pathname, NETMAP_DEVICE_NAME) == 0) {
                   int fd = open(NETMAP_DEVICE_NAME, O_RDWR);
                   if (fd < 0) {
                           return -1;
                   }
   
                   win_insert_fd_record(fd);
                   return fd;
           } else {
                   return open(pathname, flags);
           }
   }
   
   #define open win_nm_open
   
   static int
   win_nm_close(int fd)
   {
           if (fd != -1) {
                   close(fd);
                   if (win_get_netmap_handle(fd) != NULL) {
                           win_remove_fd_record(fd);
                   }
           }
           return 0;
   }
   
   #define close win_nm_close
   
   #endif /* _WIN32 */
   
   static int
   nm_is_identifier(const char *s, const char *e)
   {
           for (; s != e; s++) {
                   if (!isalnum(*s) && *s != '_') {
                           return 0;
                   }
           }
   
           return 1;
   }
   
   #define MAXERRMSG 80
   static int
   nm_parse(const char *ifname, struct nm_desc *d, char *err)
   {
           int is_vale;
           const char *port = NULL;
           const char *vpname = NULL;
           u_int namelen;
           uint32_t nr_ringid = 0, nr_flags;
           char errmsg[MAXERRMSG] = "";
           long num;
           uint16_t nr_arg2 = 0;
           enum { P_START, P_RNGSFXOK, P_GETNUM, P_FLAGS, P_FLAGSOK, P_MEMID } p_state;
   
           errno = 0;
   
           is_vale = (ifname[0] == 'v');
           if (is_vale) {
                   port = index(ifname, ':');
                   if (port == NULL) {
                           snprintf(errmsg, MAXERRMSG,
                                    "missing ':' in vale name");
                           goto fail;
                   }
   
                   if (!nm_is_identifier(ifname + 4, port)) {
                           snprintf(errmsg, MAXERRMSG, "invalid bridge name");
                           goto fail;
                   }
   
                   vpname = ++port;
           } else {
                   ifname += 7;
                   port = ifname;
           }
   
           /* scan for a separator */
           for (; *port && !index("-*^{}/@", *port); port++)
                   ;
   
           if (is_vale && !nm_is_identifier(vpname, port)) {
                   snprintf(errmsg, MAXERRMSG, "invalid bridge port name");
                   goto fail;
           }
   
           namelen = port - ifname;
           if (namelen >= sizeof(d->req.nr_name)) {
                   snprintf(errmsg, MAXERRMSG, "name too long");
                   goto fail;
           }
           memcpy(d->req.nr_name, ifname, namelen);
           d->req.nr_name[namelen] = '\0';
   
           p_state = P_START;
           nr_flags = NR_REG_ALL_NIC; /* default for no suffix */
           while (*port) {
                   switch (p_state) {
                   case P_START:
                           switch (*port) {
                           case '^': /* only SW ring */
                                   nr_flags = NR_REG_SW;
                                   p_state = P_RNGSFXOK;
                                   break;
                           case '*': /* NIC and SW */
                                   nr_flags = NR_REG_NIC_SW;
                                   p_state = P_RNGSFXOK;
                                   break;
                           case '-': /* one NIC ring pair */
                                   nr_flags = NR_REG_ONE_NIC;
                                   p_state = P_GETNUM;
                                   break;
                           case '{': /* pipe (master endpoint) */
                                   nr_flags = NR_REG_PIPE_MASTER;
                                   p_state = P_GETNUM;
                                   break;
                           case '}': /* pipe (slave endoint) */
                                   nr_flags = NR_REG_PIPE_SLAVE;
                                   p_state = P_GETNUM;
                                   break;
                           case '/': /* start of flags */
                                   p_state = P_FLAGS;
                                   break;
                           case '@': /* start of memid */
                                   p_state = P_MEMID;
                                   break;
                           default:
                                   snprintf(errmsg, MAXERRMSG, "unknown modifier: '%c'", *port);
                                   goto fail;
                           }
                           port++;
                           break;
                   case P_RNGSFXOK:
                           switch (*port) {
                           case '/':
                                   p_state = P_FLAGS;
                                   break;
                           case '@':
                                   p_state = P_MEMID;
                                   break;
                           default:
                                   snprintf(errmsg, MAXERRMSG, "unexpected character: '%c'", *port);
                                   goto fail;
                           }
                           port++;
                           break;
                   case P_GETNUM:
                           num = strtol(port, (char **)&port, 10);
                           if (num < 0 || num >= NETMAP_RING_MASK) {
                                   snprintf(errmsg, MAXERRMSG, "'%ld' out of range [0, %d)",
                                                   num, NETMAP_RING_MASK);
                                   goto fail;
                           }
                           nr_ringid = num & NETMAP_RING_MASK;
                           p_state = P_RNGSFXOK;
                           break;
                   case P_FLAGS:
                   case P_FLAGSOK:
                           if (*port == '@') {
                                   port++;
                                   p_state = P_MEMID;
                                   break;
                           }
                           switch (*port) {
                           case 'x':
                                   nr_flags |= NR_EXCLUSIVE;
                                   break;
                           case 'z':
                                   nr_flags |= NR_ZCOPY_MON;
                                   break;
                           case 't':
                                   nr_flags |= NR_MONITOR_TX;
                                   break;
                           case 'r':
                                   nr_flags |= NR_MONITOR_RX;
                                   break;
                           case 'R':
                                   nr_flags |= NR_RX_RINGS_ONLY;
                                   break;
                           case 'T':
                                   nr_flags |= NR_TX_RINGS_ONLY;
                                   break;
                           default:
                                   snprintf(errmsg, MAXERRMSG, "unrecognized flag: '%c'", *port);
                                   goto fail;
                           }
                           port++;
                           p_state = P_FLAGSOK;
                           break;
                   case P_MEMID:
                           if (nr_arg2 != 0) {
                                   snprintf(errmsg, MAXERRMSG, "double setting of memid");
                                   goto fail;
                           }
                           num = strtol(port, (char **)&port, 10);
                           if (num <= 0) {
                                   snprintf(errmsg, MAXERRMSG, "invalid memid %ld, must be >0", num);
                                   goto fail;
                           }
                           nr_arg2 = num;
                           p_state = P_RNGSFXOK;
                           break;
                   }
           }
           if (p_state != P_START && p_state != P_RNGSFXOK && p_state != P_FLAGSOK) {
                   snprintf(errmsg, MAXERRMSG, "unexpected end of port name");
                   goto fail;
           }
           ND("flags: %s %s %s %s",
                           (nr_flags & NR_EXCLUSIVE) ? "EXCLUSIVE" : "",
                           (nr_flags & NR_ZCOPY_MON) ? "ZCOPY_MON" : "",
                           (nr_flags & NR_MONITOR_TX) ? "MONITOR_TX" : "",
                           (nr_flags & NR_MONITOR_RX) ? "MONITOR_RX" : "");
   
           d->req.nr_flags |= nr_flags;
           d->req.nr_ringid |= nr_ringid;
           d->req.nr_arg2 = nr_arg2;
   
           d->self = d;
   
           return 0;
   fail:
           if (!errno)
                   errno = EINVAL;
           if (err)
                   strncpy(err, errmsg, MAXERRMSG);
           return -1;
   }
   
   /*
    * Try to open, return descriptor if successful, NULL otherwise.
    * An invalid netmap name will return errno = 0;
    * You can pass a pointer to a pre-filled nm_desc to add special
    * parameters. Flags is used as follows
    * NM_OPEN_NO_MMAP      use the memory from arg, only XXX avoid mmap
    *                      if the nr_arg2 (memory block) matches.
    * NM_OPEN_ARG1         use req.nr_arg1 from arg
    * NM_OPEN_ARG2         use req.nr_arg2 from arg
    * NM_OPEN_RING_CFG     user ring config from arg
    */
   static struct nm_desc *
   nm_open(const char *ifname, const struct nmreq *req,
           uint64_t new_flags, const struct nm_desc *arg)
   {
           struct nm_desc *d = NULL;
           const struct nm_desc *parent = arg;
           char errmsg[MAXERRMSG] = "";
           uint32_t nr_reg;
   
           if (strncmp(ifname, "netmap:", 7) &&
                           strncmp(ifname, NM_BDG_NAME, strlen(NM_BDG_NAME))) {
                   errno = 0; /* name not recognised, not an error */
                   return NULL;
           }
   
           d = (struct nm_desc *)calloc(1, sizeof(*d));
           if (d == NULL) {
                   snprintf(errmsg, MAXERRMSG, "nm_desc alloc failure");
                   errno = ENOMEM;
                   return NULL;
           }
           d->self = d;    /* set this early so nm_close() works */
           d->fd = open(NETMAP_DEVICE_NAME, O_RDWR);
           if (d->fd < 0) {
                   snprintf(errmsg, MAXERRMSG, "cannot open /dev/netmap: %s", strerror(errno));
                   goto fail;
           }
   
           if (req)
                   d->req = *req;
   
           if (!(new_flags & NM_OPEN_IFNAME)) {
                   if (nm_parse(ifname, d, errmsg) < 0)
                           goto fail;
           }
   
           d->req.nr_version = NETMAP_API;
           d->req.nr_ringid &= NETMAP_RING_MASK;
   
           /* optionally import info from parent */
           if (IS_NETMAP_DESC(parent) && new_flags) {
                   if (new_flags & NM_OPEN_ARG1)
                           D("overriding ARG1 %d", parent->req.nr_arg1);
                   d->req.nr_arg1 = new_flags & NM_OPEN_ARG1 ?
                           parent->req.nr_arg1 : 4;
                   if (new_flags & NM_OPEN_ARG2) {
                           D("overriding ARG2 %d", parent->req.nr_arg2);
                           d->req.nr_arg2 =  parent->req.nr_arg2;
                   }
                   if (new_flags & NM_OPEN_ARG3)
                           D("overriding ARG3 %d", parent->req.nr_arg3);
                   d->req.nr_arg3 = new_flags & NM_OPEN_ARG3 ?
                           parent->req.nr_arg3 : 0;
                   if (new_flags & NM_OPEN_RING_CFG) {
                           D("overriding RING_CFG");
                           d->req.nr_tx_slots = parent->req.nr_tx_slots;
                           d->req.nr_rx_slots = parent->req.nr_rx_slots;
                           d->req.nr_tx_rings = parent->req.nr_tx_rings;
                           d->req.nr_rx_rings = parent->req.nr_rx_rings;
                   }
                   if (new_flags & NM_OPEN_IFNAME) {
                           D("overriding ifname %s ringid 0x%x flags 0x%x",
                                   parent->req.nr_name, parent->req.nr_ringid,
                                   parent->req.nr_flags);
                           memcpy(d->req.nr_name, parent->req.nr_name,
                                   sizeof(d->req.nr_name));
                           d->req.nr_ringid = parent->req.nr_ringid;
                           d->req.nr_flags = parent->req.nr_flags;
                   }
           }
           /* add the *XPOLL flags */
           d->req.nr_ringid |= new_flags & (NETMAP_NO_TX_POLL | NETMAP_DO_RX_POLL);
   
           if (ioctl(d->fd, NIOCREGIF, &d->req)) {
                   snprintf(errmsg, MAXERRMSG, "NIOCREGIF failed: %s", strerror(errno));
                   goto fail;
           }
   
           nr_reg = d->req.nr_flags & NR_REG_MASK;
   
           if (nr_reg == NR_REG_SW) { /* host stack */
                   d->first_tx_ring = d->last_tx_ring = d->req.nr_tx_rings;
                   d->first_rx_ring = d->last_rx_ring = d->req.nr_rx_rings;
           } else if (nr_reg ==  NR_REG_ALL_NIC) { /* only nic */
                   d->first_tx_ring = 0;
                   d->first_rx_ring = 0;
                   d->last_tx_ring = d->req.nr_tx_rings - 1;
                   d->last_rx_ring = d->req.nr_rx_rings - 1;
           } else if (nr_reg ==  NR_REG_NIC_SW) {
                   d->first_tx_ring = 0;
                   d->first_rx_ring = 0;
                   d->last_tx_ring = d->req.nr_tx_rings;
                   d->last_rx_ring = d->req.nr_rx_rings;
           } else if (nr_reg == NR_REG_ONE_NIC) {
                   /* XXX check validity */
                   d->first_tx_ring = d->last_tx_ring =
                   d->first_rx_ring = d->last_rx_ring = d->req.nr_ringid & NETMAP_RING_MASK;
           } else { /* pipes */
                   d->first_tx_ring = d->last_tx_ring = 0;
                   d->first_rx_ring = d->last_rx_ring = 0;
           }
   
           /* if parent is defined, do nm_mmap() even if NM_OPEN_NO_MMAP is set */
           if ((!(new_flags & NM_OPEN_NO_MMAP) || parent) && nm_mmap(d, parent)) {
                   snprintf(errmsg, MAXERRMSG, "mmap failed: %s", strerror(errno));
                   goto fail;
           }
   
   
   #ifdef DEBUG_NETMAP_USER
       { /* debugging code */
           int i;
   
           D("%s tx %d .. %d %d rx %d .. %d %d", ifname,
                   d->first_tx_ring, d->last_tx_ring, d->req.nr_tx_rings,
                   d->first_rx_ring, d->last_rx_ring, d->req.nr_rx_rings);
           for (i = 0; i <= d->req.nr_tx_rings; i++) {
                   struct netmap_ring *r = NETMAP_TXRING(d->nifp, i);
                   D("TX%d %p h %d c %d t %d", i, r, r->head, r->cur, r->tail);
           }
           for (i = 0; i <= d->req.nr_rx_rings; i++) {
                   struct netmap_ring *r = NETMAP_RXRING(d->nifp, i);
                   D("RX%d %p h %d c %d t %d", i, r, r->head, r->cur, r->tail);
           }
       }
   #endif /* debugging */
   
           d->cur_tx_ring = d->first_tx_ring;
           d->cur_rx_ring = d->first_rx_ring;
           return d;
   
   fail:
           nm_close(d);
           if (errmsg[0])
                   D("%s %s", errmsg, ifname);
           if (errno == 0)
                   errno = EINVAL;
           return NULL;
   }
   
   
   static int
   nm_close(struct nm_desc *d)
   {
           /*
            * ugly trick to avoid unused warnings
            */
           static void *__xxzt[] __attribute__ ((unused))  =
                   { (void *)nm_open, (void *)nm_inject,
                     (void *)nm_dispatch, (void *)nm_nextpkt } ;
   
           if (d == NULL || d->self != d)
                   return EINVAL;
           if (d->done_mmap && d->mem)
                   munmap(d->mem, d->memsize);
           if (d->fd != -1) {
                   close(d->fd);
           }
   
           bzero(d, sizeof(*d));
           free(d);
           return 0;
   }
   
   
   static int
   nm_mmap(struct nm_desc *d, const struct nm_desc *parent)
   {
           //XXX TODO: check if mmap is already done
   
           if (IS_NETMAP_DESC(parent) && parent->mem &&
               parent->req.nr_arg2 == d->req.nr_arg2) {
                   /* do not mmap, inherit from parent */
                   D("do not mmap, inherit from parent");
                   d->memsize = parent->memsize;
                   d->mem = parent->mem;
           } else {
                   /* XXX TODO: check if memsize is too large (or there is overflow) */
                   d->memsize = d->req.nr_memsize;
                   d->mem = mmap(0, d->memsize, PROT_WRITE | PROT_READ, MAP_SHARED,
                                   d->fd, 0);
                   if (d->mem == MAP_FAILED) {
                           goto fail;
                   }
                   d->done_mmap = 1;
           }
           {
                  struct netmap_if *nifp = NETMAP_IF(d->mem, d->req.nr_offset);
                  struct netmap_ring *r = NETMAP_RXRING(nifp, d->first_rx_ring);
                  if ((void *)r == (void *)nifp) {
                          /* the descriptor is open for TX only */
                          r = NETMAP_TXRING(nifp, d->first_tx_ring);
                  }
  
                  *(struct netmap_if **)(uintptr_t)&(d->nifp) = nifp;
                  *(struct netmap_ring **)(uintptr_t)&d->some_ring = r;
                  *(void **)(uintptr_t)&d->buf_start = NETMAP_BUF(r, 0);
                  *(void **)(uintptr_t)&d->buf_end =
                          (char *)d->mem + d->memsize;
          }
  
          return 0;
  
  fail:
          return EINVAL;
  }
  
  /*
   * Same prototype as pcap_inject(), only need to cast.
   */
  static int
  nm_inject(struct nm_desc *d, const void *buf, size_t size)
  {
          u_int c, n = d->last_tx_ring - d->first_tx_ring + 1,
                  ri = d->cur_tx_ring;
  
          for (c = 0; c < n ; c++, ri++) {
                  /* compute current ring to use */
                  struct netmap_ring *ring;
                  uint32_t i, j, idx;
                  size_t rem;
  
                  if (ri > d->last_tx_ring)
                          ri = d->first_tx_ring;
                  ring = NETMAP_TXRING(d->nifp, ri);
                  rem = size;
                  j = ring->cur;
                  while (rem > ring->nr_buf_size && j != ring->tail) {
                          rem -= ring->nr_buf_size;
                          j = nm_ring_next(ring, j);
                  }
                  if (j == ring->tail && rem > 0)
                          continue;
                  i = ring->cur;
                  while (i != j) {
                          idx = ring->slot[i].buf_idx;
                          ring->slot[i].len = ring->nr_buf_size;
                          ring->slot[i].flags = NS_MOREFRAG;
                          nm_pkt_copy(buf, NETMAP_BUF(ring, idx), ring->nr_buf_size);
                          i = nm_ring_next(ring, i);
                          buf = (char *)buf + ring->nr_buf_size;
                  }
                  idx = ring->slot[i].buf_idx;
                  ring->slot[i].len = rem;
                  ring->slot[i].flags = 0;
                  nm_pkt_copy(buf, NETMAP_BUF(ring, idx), rem);
                  ring->head = ring->cur = nm_ring_next(ring, i);
                  d->cur_tx_ring = ri;
                  return size;
          }
          return 0; /* fail */
  }
  
  
  /*
   * Same prototype as pcap_dispatch(), only need to cast.
   */
  static int
  nm_dispatch(struct nm_desc *d, int cnt, nm_cb_t cb, u_char *arg)
  {
          int n = d->last_rx_ring - d->first_rx_ring + 1;
          int c, got = 0, ri = d->cur_rx_ring;
          d->hdr.buf = NULL;
          d->hdr.flags = NM_MORE_PKTS;
          d->hdr.d = d;
  
          if (cnt == 0)
                  cnt = -1;
          /* cnt == -1 means infinite, but rings have a finite amount
           * of buffers and the int is large enough that we never wrap,
           * so we can omit checking for -1
           */
          for (c=0; c < n && cnt != got; c++, ri++) {
                  /* compute current ring to use */
                  struct netmap_ring *ring;
  
                  if (ri > d->last_rx_ring)
                          ri = d->first_rx_ring;
                  ring = NETMAP_RXRING(d->nifp, ri);
                  for ( ; !nm_ring_empty(ring) && cnt != got; got++) {
                          u_int idx, i;
                          if (d->hdr.buf) { /* from previous round */
                                  cb(arg, &d->hdr, d->hdr.buf);
                          }
                          i = ring->cur;
                          idx = ring->slot[i].buf_idx;
                          /* d->cur_rx_ring doesn't change inside this loop, but
                           * set it here, so it reflects d->hdr.buf's ring */
                          d->cur_rx_ring = ri;
                          d->hdr.slot = &ring->slot[i];
                          d->hdr.buf = (u_char *)NETMAP_BUF(ring, idx);
                          // __builtin_prefetch(buf);
                          d->hdr.len = d->hdr.caplen = ring->slot[i].len;
                          d->hdr.ts = ring->ts;
                          ring->head = ring->cur = nm_ring_next(ring, i);
                  }
          }
          if (d->hdr.buf) { /* from previous round */
                  d->hdr.flags = 0;
                  cb(arg, &d->hdr, d->hdr.buf);
          }
          return got;
  }
  
  static u_char *
  nm_nextpkt(struct nm_desc *d, struct nm_pkthdr *hdr)
  {
          int ri = d->cur_rx_ring;
  
          do {
                  /* compute current ring to use */
                  struct netmap_ring *ring = NETMAP_RXRING(d->nifp, ri);
                  if (!nm_ring_empty(ring)) {
                          u_int i = ring->cur;
                          u_int idx = ring->slot[i].buf_idx;
                          u_char *buf = (u_char *)NETMAP_BUF(ring, idx);
  
                          // __builtin_prefetch(buf);
                          hdr->ts = ring->ts;
                          hdr->len = hdr->caplen = ring->slot[i].len;
                          ring->cur = nm_ring_next(ring, i);
                          /* we could postpone advancing head if we want
                           * to hold the buffer. This can be supported in
                           * the future.
                           */
                          ring->head = ring->cur;
                          d->cur_rx_ring = ri;
                          return buf;
                  }
                  ri++;
                  if (ri > d->last_rx_ring)
                          ri = d->first_rx_ring;
          } while (ri != d->cur_rx_ring);
          return NULL; /* nothing found */
  }
  
  #endif /* !HAVE_NETMAP_WITH_LIBS */
  
  #endif /* NETMAP_WITH_LIBS */
  
  #endif /* _NET_NETMAP_USER_H_ */

Cache object: b24a3a5be80d51aeb6642c37729d14d5