src/tx_ring.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.
   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 "xmalloc.h"
  21 #include "die.h"
  22 #include "tx_ring.h"
  23
  24 #ifdef HAVE_TX_RING
  25 void set_packet_loss_discard(int sock)
  26 {
  27         int ret, discard = 1;
  28
  29         ret = setsockopt(sock, SOL_PACKET, PACKET_LOSS, (void *) &discard,
  30                          sizeof(discard));
  31         if (ret < 0)
  32                 error_and_die(EXIT_FAILURE, "setsockopt: cannot set packet "
  33                               "loss");
  34 }
  35
  36 void destroy_tx_ring(int sock, struct ring *ring)
  37 {
  38         memset(&ring->layout, 0, sizeof(ring->layout));
  39         setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  40                    sizeof(ring->layout));
  41
  42         munmap(ring->mm_space, ring->mm_len);
  43         ring->mm_len = 0;
  44
  45         xfree(ring->frames);
  46 }
  47
  48 void setup_tx_ring_layout(int sock, struct ring *ring, unsigned int size)
  49 {
  50         memset(&ring->layout, 0, sizeof(ring->layout));
  51         ring->layout.tp_block_size = getpagesize() << 2;
  52         ring->layout.tp_frame_size = TPACKET_ALIGNMENT << 10;
  53         ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
  54         ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  55                                    ring->layout.tp_frame_size *
  56                                    ring->layout.tp_block_nr;
  57
  58         assert(ring->layout.tp_block_size >= ring->layout.tp_frame_size);
  59         assert((ring->layout.tp_block_size % ring->layout.tp_frame_size) == 0);
  60 }
  61
  62 void create_tx_ring(int sock, struct ring *ring)
  63 {
  64         int ret;
  65 retry:
  66         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  67                          sizeof(ring->layout));
  68         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  69                 ring->layout.tp_block_nr >>= 1;
  70                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  71                                            ring->layout.tp_frame_size *
  72                                            ring->layout.tp_block_nr;
  73                 goto retry;
  74         }
  75
  76         if (ret < 0)
  77                 error_and_die(EXIT_FAILURE, "Cannot allocate TX_RING!\n");
  78
  79         ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
  80
  81         printf("TX: %.2f MB, %u Frames each %u Byte allocated\n",
  82                1.f * ring->mm_len / (1 << 20),
  83                ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  84 }
  85
  86 void mmap_tx_ring(int sock, struct ring *ring)
  87 {
  88         ring->mm_space = mmap(0, ring->mm_len, PROT_READ | PROT_WRITE,
  89                               MAP_SHARED, sock, 0);
  90         if (ring->mm_space == MAP_FAILED) {
  91                 destroy_tx_ring(sock, ring);
  92                 error_and_die(EXIT_FAILURE, "Cannot mmap TX_RING!\n");
  93         }
  94 }
  95
  96 void alloc_tx_ring_frames(struct ring *ring)
  97 {
  98         int i;
  99
 100         ring->frames = xzmalloc(ring->layout.tp_frame_nr *
 101                                 sizeof(*ring->frames));
 102
 103         for (i = 0; i < ring->layout.tp_frame_nr; ++i) {
 104                 ring->frames[i].iov_len = ring->layout.tp_frame_size;
 105                 ring->frames[i].iov_base = ring->mm_space +
 106                                            (i * ring->layout.tp_frame_size);
 107         }
 108 }
 109
 110 void bind_tx_ring(int sock, struct ring *ring, int ifindex)
 111 {
 112         memset(&ring->s_ll, 0, sizeof(ring->s_ll));
 113         ring->s_ll.sll_family = AF_PACKET;
 114         ring->s_ll.sll_protocol = htons(ETH_P_ALL);
 115         ring->s_ll.sll_ifindex = ifindex;
 116         ring->s_ll.sll_hatype = 0;
 117         ring->s_ll.sll_halen = 0;
 118         ring->s_ll.sll_pkttype = 0;
 119
 120         int ret = bind(sock, (struct sockaddr *) &ring->s_ll,
 121                        sizeof(ring->s_ll));
 122         if (ret < 0) {
 123                 destroy_tx_ring(sock, ring);
 124                 error_and_die(EXIT_FAILURE, "Cannot bind TX_RING!\n");
 125         }
 126 }
 127
 128 int pull_and_flush_tx_ring(int sock)
 129 {
 130         /* Flush buffers with TP_STATUS_SEND_REQUEST */
 131         return sendto(sock, NULL, 0, MSG_DONTWAIT, NULL, 0);
 132 }
 133
 134 #endif /* HAVE_TX_RING */