src/ring_tx.c

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