ring_rx.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * By Daniel Borkmann <daniel@netsniff-ng.org>
   4  * Copyright 2009, 2010 Daniel Borkmann.
   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 "xmalloc.h"
  19 #include "die.h"
  20 #include "ring_rx.h"
  21 #include "built_in.h"
  22
  23 void destroy_rx_ring(int sock, struct ring *ring)
  24 {
  25         fmemset(&ring->layout, 0, sizeof(ring->layout));
  26         setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->layout,
  27                    sizeof(ring->layout));
  28
  29         munmap(ring->mm_space, ring->mm_len);
  30         ring->mm_len = 0;
  31
  32         xfree(ring->frames);
  33 }
  34
  35 void setup_rx_ring_layout(int sock, struct ring *ring, unsigned int size,
  36                           int jumbo_support)
  37 {
  38         fmemset(&ring->layout, 0, sizeof(ring->layout));
  39
  40         ring->layout.tp_block_size = (jumbo_support ?
  41                                       getpagesize() << 4 :
  42                                       getpagesize() << 2);
  43         ring->layout.tp_frame_size = (jumbo_support ?
  44                                       TPACKET_ALIGNMENT << 12 :
  45                                       TPACKET_ALIGNMENT << 7);
  46         ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
  47         ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  48                                    ring->layout.tp_frame_size *
  49                                    ring->layout.tp_block_nr;
  50
  51         bug_on(ring->layout.tp_block_size < ring->layout.tp_frame_size);
  52         bug_on((ring->layout.tp_block_size % ring->layout.tp_frame_size) != 0);
  53         bug_on((ring->layout.tp_block_size % getpagesize()) != 0);
  54 }
  55
  56 void create_rx_ring(int sock, struct ring *ring, int verbose)
  57 {
  58         int ret;
  59
  60         set_sockopt_tpacket(sock);
  61 retry:
  62         ret = setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->layout,
  63                          sizeof(ring->layout));
  64         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  65                 ring->layout.tp_block_nr >>= 1;
  66                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  67                                            ring->layout.tp_frame_size *
  68                                            ring->layout.tp_block_nr;
  69                 goto retry;
  70         }
  71
  72         if (ret < 0)
  73                 panic("Cannot allocate RX_RING!\n");
  74
  75         ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
  76
  77         if (verbose) {
  78                 printf("RX: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
  79                        (long double) ring->mm_len / (1 << 20),
  80                        ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  81         }
  82 }
  83
  84 void mmap_rx_ring(int sock, struct ring *ring)
  85 {
  86         ring->mm_space = mmap(0, ring->mm_len, PROT_READ | PROT_WRITE,
  87                               MAP_SHARED | MAP_LOCKED | MAP_POPULATE, sock, 0);
  88         if (ring->mm_space == MAP_FAILED) {
  89                 destroy_rx_ring(sock, ring);
  90                 panic("Cannot mmap RX_RING!\n");
  91         }
  92 }
  93
  94 void alloc_rx_ring_frames(struct ring *ring)
  95 {
  96         int i;
  97         size_t len = ring->layout.tp_frame_nr * sizeof(*ring->frames);
  98
  99         ring->frames = xmalloc_aligned(len, CO_CACHE_LINE_SIZE);
 100         fmemset(ring->frames, 0, len);
 101
 102         for (i = 0; i < ring->layout.tp_frame_nr; ++i) {
 103                 ring->frames[i].iov_len = ring->layout.tp_frame_size;
 104                 ring->frames[i].iov_base = ring->mm_space +
 105                                            (i * ring->layout.tp_frame_size);
 106         }
 107 }
 108
 109 void bind_rx_ring(int sock, struct ring *ring, int ifindex)
 110 {
 111         int ret;
 112         /*
 113          * The RX_RING registers itself to the networking stack with
 114          * dev_add_pack(), so we have one single RX_RING for all devs
 115          * otherwise you'll get the packet twice.
 116          */
 117         fmemset(&ring->s_ll, 0, sizeof(ring->s_ll));
 118
 119         ring->s_ll.sll_family = AF_PACKET;
 120         ring->s_ll.sll_protocol = htons(ETH_P_ALL);
 121         ring->s_ll.sll_ifindex = ifindex;
 122         ring->s_ll.sll_hatype = 0;
 123         ring->s_ll.sll_halen = 0;
 124         ring->s_ll.sll_pkttype = 0;
 125
 126         ret = bind(sock, (struct sockaddr *) &ring->s_ll, sizeof(ring->s_ll));
 127         if (ret < 0) {
 128                 destroy_rx_ring(sock, ring);
 129                 panic("Cannot bind RX_RING!\n");
 130         }
 131 }