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         fmemset(&ring->layout, 0, sizeof(ring->layout));
  37
  38         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  39                          sizeof(ring->layout));
  40         if (unlikely(ret))
  41                 panic("Cannot destroy the TX_RING!\n");
  42
  43         munmap(ring->mm_space, ring->mm_len);
  44         ring->mm_len = 0;
  45
  46         xfree(ring->frames);
  47 }
  48
  49 void setup_tx_ring_layout(int sock, struct ring *ring, unsigned int size,
  50                           int jumbo_support)
  51 {
  52         fmemset(&ring->layout, 0, sizeof(ring->layout));
  53
  54         ring->layout.tp_block_size = (jumbo_support ?
  55                                       getpagesize() << 4 :
  56                                       getpagesize() << 2);
  57         ring->layout.tp_frame_size = (jumbo_support ?
  58                                       TPACKET_ALIGNMENT << 12 :
  59                                       TPACKET_ALIGNMENT << 7);
  60         ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
  61         ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  62                                    ring->layout.tp_frame_size *
  63                                    ring->layout.tp_block_nr;
  64
  65         bug_on(ring->layout.tp_block_size < ring->layout.tp_frame_size);
  66         bug_on((ring->layout.tp_block_size % ring->layout.tp_frame_size) != 0);
  67         bug_on((ring->layout.tp_block_size % getpagesize()) != 0);
  68 }
  69
  70 void create_tx_ring(int sock, struct ring *ring, int verbose)
  71 {
  72         int ret;
  73
  74         set_sockopt_tpacket(sock);
  75 retry:
  76         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  77                          sizeof(ring->layout));
  78         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  79                 ring->layout.tp_block_nr >>= 1;
  80                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  81                                            ring->layout.tp_frame_size *
  82                                            ring->layout.tp_block_nr;
  83                 goto retry;
  84         }
  85
  86         if (ret < 0)
  87                 panic("Cannot allocate TX_RING!\n");
  88
  89         ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
  90
  91         if (verbose) {
  92                 printf("TX: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
  93                        (long double) ring->mm_len / (1 << 20),
  94                        ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  95         }
  96 }
  97
  98 void mmap_tx_ring(int sock, struct ring *ring)
  99 {
 100         ring->mm_space = mmap(0, ring->mm_len, PROT_READ | PROT_WRITE,
 101                               MAP_SHARED | MAP_LOCKED | MAP_POPULATE, sock, 0);
 102         if (ring->mm_space == MAP_FAILED) {
 103                 destroy_tx_ring(sock, ring);
 104                 panic("Cannot mmap TX_RING!\n");
 105         }
 106 }
 107
 108 void alloc_tx_ring_frames(struct ring *ring)
 109 {
 110         int i;
 111         size_t len = ring->layout.tp_frame_nr * sizeof(*ring->frames);
 112
 113         ring->frames = xmalloc_aligned(len, CO_CACHE_LINE_SIZE);
 114         fmemset(ring->frames, 0, len);
 115
 116         for (i = 0; i < ring->layout.tp_frame_nr; ++i) {
 117                 ring->frames[i].iov_len = ring->layout.tp_frame_size;
 118                 ring->frames[i].iov_base = ring->mm_space +
 119                                            (i * ring->layout.tp_frame_size);
 120         }
 121 }
 122
 123 void bind_tx_ring(int sock, struct ring *ring, int ifindex)
 124 {
 125         int ret;
 126
 127         fmemset(&ring->s_ll, 0, sizeof(ring->s_ll));
 128
 129         ring->s_ll.sll_family = AF_PACKET;
 130         ring->s_ll.sll_protocol = htons(ETH_P_ALL);
 131         ring->s_ll.sll_ifindex = ifindex;
 132         ring->s_ll.sll_hatype = 0;
 133         ring->s_ll.sll_halen = 0;
 134         ring->s_ll.sll_pkttype = 0;
 135
 136         ret = bind(sock, (struct sockaddr *) &ring->s_ll, sizeof(ring->s_ll));
 137         if (ret < 0) {
 138                 destroy_tx_ring(sock, ring);
 139                 panic("Cannot bind TX_RING!\n");
 140         }
 141 }