ring_rx.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009, 2010 Daniel Borkmann.
   4  * Subject to the GPL, version 2.
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include <unistd.h>
  11 #include <sys/mman.h>
  12 #include <sys/types.h>
  13 #include <sys/socket.h>
  14 #include <arpa/inet.h>
  15 #include <linux/if_ether.h>
  16
  17 #include "xmalloc.h"
  18 #include "die.h"
  19 #include "ring_rx.h"
  20 #include "built_in.h"
  21
  22 void destroy_rx_ring(int sock, struct ring *ring)
  23 {
  24         int ret;
  25
  26         munmap(ring->mm_space, ring->mm_len);
  27         ring->mm_len = 0;
  28
  29         fmemset(&ring->layout, 0, sizeof(ring->layout));
  30         ret = setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->layout,
  31                          sizeof(ring->layout));
  32         if (unlikely(ret))
  33                 panic("Cannot destroy the RX_RING: %s!\n", strerror(errno));
  34
  35         xfree(ring->frames);
  36 }
  37
  38 void setup_rx_ring_layout(int sock, struct ring *ring, unsigned int size,
  39                           int jumbo_support)
  40 {
  41         fmemset(&ring->layout, 0, sizeof(ring->layout));
  42
  43         ring->layout.tp_block_size = (jumbo_support ?
  44                                       getpagesize() << 4 :
  45                                       getpagesize() << 2);
  46         ring->layout.tp_frame_size = (jumbo_support ?
  47                                       TPACKET_ALIGNMENT << 12 :
  48                                       TPACKET_ALIGNMENT << 7);
  49         ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
  50         ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  51                                    ring->layout.tp_frame_size *
  52                                    ring->layout.tp_block_nr;
  53
  54         bug_on(ring->layout.tp_block_size < ring->layout.tp_frame_size);
  55         bug_on((ring->layout.tp_block_size % ring->layout.tp_frame_size) != 0);
  56         bug_on((ring->layout.tp_block_size % getpagesize()) != 0);
  57 }
  58
  59 void create_rx_ring(int sock, struct ring *ring, int verbose)
  60 {
  61         int ret;
  62
  63         set_sockopt_tpacket(sock);
  64 retry:
  65         ret = setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->layout,
  66                          sizeof(ring->layout));
  67         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  68                 ring->layout.tp_block_nr >>= 1;
  69                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  70                                            ring->layout.tp_frame_size *
  71                                            ring->layout.tp_block_nr;
  72                 goto retry;
  73         }
  74
  75         if (ret < 0)
  76                 panic("Cannot allocate RX_RING!\n");
  77
  78         ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
  79
  80         if (verbose) {
  81                 printf("RX: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
  82                        (long double) ring->mm_len / (1 << 20),
  83                        ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  84         }
  85 }
  86
  87 void mmap_rx_ring(int sock, struct ring *ring)
  88 {
  89         ring->mm_space = mmap(0, ring->mm_len, PROT_READ | PROT_WRITE,
  90                               MAP_SHARED | MAP_LOCKED | MAP_POPULATE, sock, 0);
  91         if (ring->mm_space == MAP_FAILED) {
  92                 destroy_rx_ring(sock, ring);
  93                 panic("Cannot mmap RX_RING!\n");
  94         }
  95 }
  96
  97 void alloc_rx_ring_frames(struct ring *ring)
  98 {
  99         int i;
 100         size_t len = ring->layout.tp_frame_nr * sizeof(*ring->frames);
 101
 102         ring->frames = xmalloc_aligned(len, CO_CACHE_LINE_SIZE);
 103         fmemset(ring->frames, 0, len);
 104
 105         for (i = 0; i < ring->layout.tp_frame_nr; ++i) {
 106                 ring->frames[i].iov_len = ring->layout.tp_frame_size;
 107                 ring->frames[i].iov_base = ring->mm_space +
 108                                            (i * ring->layout.tp_frame_size);
 109         }
 110 }
 111
 112 void bind_rx_ring(int sock, struct ring *ring, int ifindex)
 113 {
 114         int ret;
 115         /*
 116          * The RX_RING registers itself to the networking stack with
 117          * dev_add_pack(), so we have one single RX_RING for all devs
 118          * otherwise you'll get the packet twice.
 119          */
 120         fmemset(&ring->s_ll, 0, sizeof(ring->s_ll));
 121
 122         ring->s_ll.sll_family = AF_PACKET;
 123         ring->s_ll.sll_protocol = htons(ETH_P_ALL);
 124         ring->s_ll.sll_ifindex = ifindex;
 125         ring->s_ll.sll_hatype = 0;
 126         ring->s_ll.sll_halen = 0;
 127         ring->s_ll.sll_pkttype = 0;
 128
 129         ret = bind(sock, (struct sockaddr *) &ring->s_ll, sizeof(ring->s_ll));
 130         if (ret < 0) {
 131                 destroy_rx_ring(sock, ring);
 132                 panic("Cannot bind RX_RING!\n");
 133         }
 134 }