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