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 <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)
  67 {
  68         int ret;
  69 retry:
  70         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  71                          sizeof(ring->layout));
  72         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  73                 ring->layout.tp_block_nr >>= 1;
  74                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  75                                            ring->layout.tp_frame_size *
  76                                            ring->layout.tp_block_nr;
  77                 goto retry;
  78         }
  79
  80         if (ret < 0)
  81                 panic("Cannot allocate TX_RING!\n");
  82
  83         ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
  84
  85         printf("TX: %.2f MiB, %u Frames, each %u Byte allocated\n",
  86                1.f * ring->mm_len / (1 << 20),
  87                ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  88 }
  89
  90 void mmap_tx_ring(int sock, struct ring *ring)
  91 {
  92         ring->mm_space = mmap(0, ring->mm_len, PROT_READ | PROT_WRITE,
  93                               MAP_SHARED | MAP_LOCKED, sock, 0);
  94         if (ring->mm_space == MAP_FAILED) {
  95                 destroy_tx_ring(sock, ring);
  96                 panic("Cannot mmap TX_RING!\n");
  97         }
  98 }
  99
 100 void alloc_tx_ring_frames(struct ring *ring)
 101 {
 102         int i;
 103         size_t len = ring->layout.tp_frame_nr * sizeof(*ring->frames);
 104
 105         ring->frames = xmalloc_aligned(len, CO_CACHE_LINE_SIZE);
 106         fmemset(ring->frames, 0, len);
 107
 108         for (i = 0; i < ring->layout.tp_frame_nr; ++i) {
 109                 ring->frames[i].iov_len = ring->layout.tp_frame_size;
 110                 ring->frames[i].iov_base = ring->mm_space +
 111                                            (i * ring->layout.tp_frame_size);
 112         }
 113 }
 114
 115 void bind_tx_ring(int sock, struct ring *ring, int ifindex)
 116 {
 117         int ret;
 118
 119         fmemset(&ring->s_ll, 0, sizeof(ring->s_ll));
 120
 121         ring->s_ll.sll_family = AF_PACKET;
 122         ring->s_ll.sll_protocol = htons(ETH_P_ALL);
 123         ring->s_ll.sll_ifindex = ifindex;
 124         ring->s_ll.sll_hatype = 0;
 125         ring->s_ll.sll_halen = 0;
 126         ring->s_ll.sll_pkttype = 0;
 127
 128         ret = bind(sock, (struct sockaddr *) &ring->s_ll, sizeof(ring->s_ll));
 129         if (ret < 0) {
 130                 destroy_tx_ring(sock, ring);
 131                 panic("Cannot bind TX_RING!\n");
 132         }
 133 }