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         fmemset(&ring->layout, 0, sizeof(ring->layout));
  27
  28         ret = setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->layout,
  29                          sizeof(ring->layout));
  30         if (unlikely(ret))
  31                 panic("Cannot destroy the RX_RING!\n");
  32
  33         munmap(ring->mm_space, ring->mm_len);
  34         ring->mm_len = 0;
  35
  36         xfree(ring->frames);
  37 }
  38
  39 void setup_rx_ring_layout(int sock, struct ring *ring, unsigned int size,
  40                           int jumbo_support)
  41 {
  42         fmemset(&ring->layout, 0, sizeof(ring->layout));
  43
  44         ring->layout.tp_block_size = (jumbo_support ?
  45                                       getpagesize() << 4 :
  46                                       getpagesize() << 2);
  47         ring->layout.tp_frame_size = (jumbo_support ?
  48                                       TPACKET_ALIGNMENT << 12 :
  49                                       TPACKET_ALIGNMENT << 7);
  50         ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
  51         ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  52                                    ring->layout.tp_frame_size *
  53                                    ring->layout.tp_block_nr;
  54
  55         bug_on(ring->layout.tp_block_size < ring->layout.tp_frame_size);
  56         bug_on((ring->layout.tp_block_size % ring->layout.tp_frame_size) != 0);
  57         bug_on((ring->layout.tp_block_size % getpagesize()) != 0);
  58 }
  59
  60 void create_rx_ring(int sock, struct ring *ring, int verbose)
  61 {
  62         int ret;
  63
  64         set_sockopt_tpacket(sock);
  65 retry:
  66         ret = setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->layout,
  67                          sizeof(ring->layout));
  68         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  69                 ring->layout.tp_block_nr >>= 1;
  70                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  71                                            ring->layout.tp_frame_size *
  72                                            ring->layout.tp_block_nr;
  73                 goto retry;
  74         }
  75
  76         if (ret < 0)
  77                 panic("Cannot allocate RX_RING!\n");
  78
  79         ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
  80
  81         if (verbose) {
  82                 printf("RX: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
  83                        (long double) ring->mm_len / (1 << 20),
  84                        ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  85         }
  86 }
  87
  88 void mmap_rx_ring(int sock, struct ring *ring)
  89 {
  90         ring->mm_space = mmap(0, ring->mm_len, PROT_READ | PROT_WRITE,
  91                               MAP_SHARED | MAP_LOCKED | MAP_POPULATE, sock, 0);
  92         if (ring->mm_space == MAP_FAILED) {
  93                 destroy_rx_ring(sock, ring);
  94                 panic("Cannot mmap RX_RING!\n");
  95         }
  96 }
  97
  98 void alloc_rx_ring_frames(struct ring *ring)
  99 {
 100         int i;
 101         size_t len = ring->layout.tp_frame_nr * sizeof(*ring->frames);
 102
 103         ring->frames = xmalloc_aligned(len, CO_CACHE_LINE_SIZE);
 104         fmemset(ring->frames, 0, len);
 105
 106         for (i = 0; i < ring->layout.tp_frame_nr; ++i) {
 107                 ring->frames[i].iov_len = ring->layout.tp_frame_size;
 108                 ring->frames[i].iov_base = ring->mm_space +
 109                                            (i * ring->layout.tp_frame_size);
 110         }
 111 }
 112
 113 void bind_rx_ring(int sock, struct ring *ring, int ifindex)
 114 {
 115         int ret;
 116         /*
 117          * The RX_RING registers itself to the networking stack with
 118          * dev_add_pack(), so we have one single RX_RING for all devs
 119          * otherwise you'll get the packet twice.
 120          */
 121         fmemset(&ring->s_ll, 0, sizeof(ring->s_ll));
 122
 123         ring->s_ll.sll_family = AF_PACKET;
 124         ring->s_ll.sll_protocol = htons(ETH_P_ALL);
 125         ring->s_ll.sll_ifindex = ifindex;
 126         ring->s_ll.sll_hatype = 0;
 127         ring->s_ll.sll_halen = 0;
 128         ring->s_ll.sll_pkttype = 0;
 129
 130         ret = bind(sock, (struct sockaddr *) &ring->s_ll, sizeof(ring->s_ll));
 131         if (ret < 0) {
 132                 destroy_rx_ring(sock, ring);
 133                 panic("Cannot bind RX_RING!\n");
 134         }
 135 }