ring_tx.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009, 2010 Daniel Borkmann.
   4  * Copyright 2009, 2010 Emmanuel Roullit.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <unistd.h>
  12 #include <sys/mman.h>
  13 #include <sys/types.h>
  14 #include <sys/socket.h>
  15 #include <arpa/inet.h>
  16 #include <linux/if_ether.h>
  17
  18 #include "die.h"
  19 #include "xmalloc.h"
  20 #include "ring_tx.h"
  21 #include "built_in.h"
  22
  23 void set_packet_loss_discard(int sock)
  24 {
  25         int ret, discard = 1;
  26         ret = setsockopt(sock, SOL_PACKET, PACKET_LOSS, (void *) &discard,
  27                          sizeof(discard));
  28         if (ret < 0)
  29                 panic("setsockopt: cannot set packet loss");
  30 }
  31
  32 void destroy_tx_ring(int sock, struct ring *ring)
  33 {
  34         int ret;
  35
  36         munmap(ring->mm_space, ring->mm_len);
  37         ring->mm_len = 0;
  38
  39         fmemset(&ring->layout, 0, sizeof(ring->layout));
  40         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  41                          sizeof(ring->layout));
  42         if (unlikely(ret))
  43                 panic("Cannot destroy the TX_RING: %s!\n", strerror(errno));
  44
  45         xfree(ring->frames);
  46 }
  47
  48 void setup_tx_ring_layout(int sock, struct ring *ring, unsigned int size,
  49                           int jumbo_support)
  50 {
  51         fmemset(&ring->layout, 0, sizeof(ring->layout));
  52
  53         ring->layout.tp_block_size = (jumbo_support ?
  54                                       getpagesize() << 4 :
  55                                       getpagesize() << 2);
  56         ring->layout.tp_frame_size = (jumbo_support ?
  57                                       TPACKET_ALIGNMENT << 12 :
  58                                       TPACKET_ALIGNMENT << 7);
  59         ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
  60         ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  61                                    ring->layout.tp_frame_size *
  62                                    ring->layout.tp_block_nr;
  63
  64         bug_on(ring->layout.tp_block_size < ring->layout.tp_frame_size);
  65         bug_on((ring->layout.tp_block_size % ring->layout.tp_frame_size) != 0);
  66         bug_on((ring->layout.tp_block_size % getpagesize()) != 0);
  67 }
  68
  69 void create_tx_ring(int sock, struct ring *ring, int verbose)
  70 {
  71         int ret;
  72
  73         set_sockopt_tpacket(sock);
  74 retry:
  75         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  76                          sizeof(ring->layout));
  77         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  78                 ring->layout.tp_block_nr >>= 1;
  79                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  80                                            ring->layout.tp_frame_size *
  81                                            ring->layout.tp_block_nr;
  82                 goto retry;
  83         }
  84
  85         if (ret < 0)
  86                 panic("Cannot allocate TX_RING!\n");
  87
  88         ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
  89
  90         if (verbose) {
  91                 printf("TX: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
  92                        (long double) ring->mm_len / (1 << 20),
  93                        ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  94         }
  95 }
  96
  97 void mmap_tx_ring(int sock, struct ring *ring)
  98 {
  99         ring->mm_space = mmap(0, ring->mm_len, PROT_READ | PROT_WRITE,
 100                               MAP_SHARED | MAP_LOCKED | MAP_POPULATE, sock, 0);
 101         if (ring->mm_space == MAP_FAILED) {
 102                 destroy_tx_ring(sock, ring);
 103                 panic("Cannot mmap TX_RING!\n");
 104         }
 105 }
 106
 107 void alloc_tx_ring_frames(struct ring *ring)
 108 {
 109         int i;
 110         size_t len = ring->layout.tp_frame_nr * sizeof(*ring->frames);
 111
 112         ring->frames = xmalloc_aligned(len, CO_CACHE_LINE_SIZE);
 113         fmemset(ring->frames, 0, len);
 114
 115         for (i = 0; i < ring->layout.tp_frame_nr; ++i) {
 116                 ring->frames[i].iov_len = ring->layout.tp_frame_size;
 117                 ring->frames[i].iov_base = ring->mm_space +
 118                                            (i * ring->layout.tp_frame_size);
 119         }
 120 }
 121
 122 void bind_tx_ring(int sock, struct ring *ring, int ifindex)
 123 {
 124         int ret;
 125
 126         fmemset(&ring->s_ll, 0, sizeof(ring->s_ll));
 127
 128         ring->s_ll.sll_family = AF_PACKET;
 129         ring->s_ll.sll_protocol = htons(ETH_P_ALL);
 130         ring->s_ll.sll_ifindex = ifindex;
 131         ring->s_ll.sll_hatype = 0;
 132         ring->s_ll.sll_halen = 0;
 133         ring->s_ll.sll_pkttype = 0;
 134
 135         ret = bind(sock, (struct sockaddr *) &ring->s_ll, sizeof(ring->s_ll));
 136         if (ret < 0) {
 137                 destroy_tx_ring(sock, ring);
 138                 panic("Cannot bind TX_RING!\n");
 139         }
 140 }