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