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