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                           bool jumbo_support, bool v3)
  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
  47         ring->layout.tp_frame_size = (jumbo_support ?
  48                                       TPACKET_ALIGNMENT << 12 :
  49                                       TPACKET_ALIGNMENT << 7);
  50
  51         ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
  52         ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  53                                    ring->layout.tp_frame_size *
  54                                    ring->layout.tp_block_nr;
  55         if (v3) {
  56                 /* Pass out, if this will ever change and we do crap on it! */
  57                 build_bug_on(offsetof(struct tpacket_req, tp_frame_nr) !=
  58                              offsetof(struct tpacket_req3, tp_frame_nr) &&
  59                              sizeof(struct tpacket_req) !=
  60                              offsetof(struct tpacket_req3, tp_retire_blk_tov));
  61
  62                 ring->layout3.tp_retire_blk_tov = 100; /* 0: let kernel decide */
  63                 ring->layout3.tp_sizeof_priv = 0;
  64                 ring->layout3.tp_feature_req_word = 0;
  65
  66                 set_sockopt_tpacket_v3(sock);
  67         } else {
  68                 set_sockopt_tpacket_v2(sock);
  69         }
  70
  71         ring_verify_layout(ring);
  72 }
  73
  74 void create_rx_ring(int sock, struct ring *ring, int verbose)
  75 {
  76         int ret;
  77         bool v3 = get_sockopt_tpacket(sock) == TPACKET_V3;
  78
  79 retry:
  80         ret = setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->raw,
  81                          v3 ? sizeof(ring->layout3) : sizeof(ring->layout));
  82
  83         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  84                 ring->layout.tp_block_nr >>= 1;
  85                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  86                                            ring->layout.tp_frame_size *
  87                                            ring->layout.tp_block_nr;
  88                 goto retry;
  89         }
  90         if (ret < 0)
  91                 panic("Cannot allocate RX_RING!\n");
  92
  93         ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
  94
  95         if (verbose) {
  96                 printf("RX: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
  97                        (long double) ring->mm_len / (1 << 20),
  98                        ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  99         }
 100 }
 101
 102 void mmap_rx_ring(int sock, struct ring *ring)
 103 {
 104         mmap_ring_generic(sock, ring);
 105 }
 106
 107 void alloc_rx_ring_frames(int sock, struct ring *ring)
 108 {
 109         int num;
 110         size_t size;
 111         bool v3 = get_sockopt_tpacket(sock) == TPACKET_V3;
 112
 113         if (v3) {
 114                 num = ring->layout3.tp_block_nr;
 115                 size = ring->layout3.tp_block_size;
 116         } else {
 117                 num = ring->layout.tp_frame_nr;
 118                 size = ring->layout.tp_frame_size;
 119         }
 120
 121         alloc_ring_frames_generic(ring, num, size);
 122 }
 123
 124 void bind_rx_ring(int sock, struct ring *ring, int ifindex)
 125 {
 126         bind_ring_generic(sock, ring, ifindex);
 127 }