ring_tx.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009, 2010 Daniel Borkmann.
   4  * Copyright 2009, 2010 Emmanuel Roullit.
   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 "die.h"
  19 #include "xmalloc.h"
  20 #include "ring_tx.h"
  21 #include "built_in.h"
  22
  23 static void set_packet_loss_discard(int sock)
  24 {
  25         int ret, discard = 1;
  26         ret = setsockopt(sock, SOL_PACKET, PACKET_LOSS, (void *) &discard,
  27                          sizeof(discard));
  28         if (ret < 0)
  29                 panic("setsockopt: cannot set packet loss");
  30 }
  31
  32 void destroy_tx_ring(int sock, struct ring *ring)
  33 {
  34         int ret;
  35
  36         munmap(ring->mm_space, ring->mm_len);
  37         ring->mm_len = 0;
  38
  39         fmemset(&ring->layout, 0, sizeof(ring->layout));
  40         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  41                          sizeof(ring->layout));
  42         if (unlikely(ret))
  43                 panic("Cannot destroy the TX_RING: %s!\n", strerror(errno));
  44
  45         xfree(ring->frames);
  46 }
  47
  48 static void setup_tx_ring_layout(int sock, struct ring *ring, size_t size,
  49                                  bool jumbo_support)
  50 {
  51         fmemset(&ring->layout, 0, sizeof(ring->layout));
  52
  53         ring->layout.tp_block_size = (jumbo_support ?
  54                                       RUNTIME_PAGE_SIZE << 4 :
  55                                       RUNTIME_PAGE_SIZE << 2);
  56
  57         ring->layout.tp_frame_size = (jumbo_support ?
  58                                       TPACKET_ALIGNMENT << 12 :
  59                                       TPACKET_ALIGNMENT << 7);
  60
  61         ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
  62         ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  63                                    ring->layout.tp_frame_size *
  64                                    ring->layout.tp_block_nr;
  65
  66         set_sockopt_tpacket_v2(sock);
  67
  68         ring_verify_layout(ring);
  69 }
  70
  71 static void create_tx_ring(int sock, struct ring *ring, bool verbose)
  72 {
  73         int ret;
  74 retry:
  75         ret = setsockopt(sock, SOL_PACKET, PACKET_TX_RING, &ring->layout,
  76                          sizeof(ring->layout));
  77
  78         if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
  79                 ring->layout.tp_block_nr >>= 1;
  80                 ring->layout.tp_frame_nr = ring->layout.tp_block_size /
  81                                            ring->layout.tp_frame_size *
  82                                            ring->layout.tp_block_nr;
  83                 goto retry;
  84         }
  85
  86         if (ret < 0)
  87                 panic("Cannot allocate TX_RING!\n");
  88
  89         ring->mm_len = (size_t) ring->layout.tp_block_size * ring->layout.tp_block_nr;
  90
  91         if (verbose) {
  92                 printf("TX,V2: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
  93                        (long double) ring->mm_len / (1 << 20),
  94                        ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
  95         }
  96 }
  97
  98 static void alloc_tx_ring_frames(int sock __maybe_unused, struct ring *ring)
  99 {
 100         alloc_ring_frames_generic(ring, ring->layout.tp_frame_nr,
 101                                   ring->layout.tp_frame_size);
 102 }
 103
 104 void ring_tx_setup(struct ring *ring, int sock, size_t size, int ifindex,
 105                    bool jumbo_support, bool verbose)
 106 {
 107         fmemset(ring, 0, sizeof(*ring));
 108         set_packet_loss_discard(sock);
 109         setup_tx_ring_layout(sock, ring, size, jumbo_support);
 110         create_tx_ring(sock, ring, verbose);
 111         mmap_ring_generic(sock, ring);
 112         alloc_tx_ring_frames(sock, ring);
 113         bind_ring_generic(sock, ring, ifindex, true);
 114 }