ring.h

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009, 2010 Daniel Borkmann.
   4  * Subject to the GPL, version 2.
   5  */
   6
   7 #ifndef RING_H
   8 #define RING_H
   9
  10 /*
  11  * "I love the smell of 10GbE in the morning. Smells like ... victory."
  12  *     - W. Richard Stevens, "Secret Teachings of the UNIX Environment"
  13  */
  14
  15 #include <stdio.h>
  16 #include <stdint.h>
  17 #include <linux/if_packet.h>
  18 #include <linux/socket.h>
  19 #include <linux/sockios.h>
  20 #include <sys/ioctl.h>
  21 #include <string.h>
  22 #include <poll.h>
  23 #include <sys/poll.h>
  24
  25 #include "built_in.h"
  26 #include "die.h"
  27 #include "dev.h"
  28 #include "config.h"
  29
  30 union tpacket_uhdr {
  31         struct tpacket_hdr  *h1;
  32         struct tpacket2_hdr *h2;
  33 #ifdef HAVE_TPACKET3
  34         struct tpacket3_hdr *h3;
  35 #endif
  36         void *raw;
  37 };
  38
  39 struct frame_map {
  40         struct tpacket2_hdr tp_h __aligned_tpacket;
  41         struct sockaddr_ll s_ll __align_tpacket(sizeof(struct tpacket2_hdr));
  42 };
  43
  44 #ifdef HAVE_TPACKET3
  45 struct block_desc {
  46         uint32_t version;
  47         uint32_t offset_to_priv;
  48         struct tpacket_hdr_v1 h1;
  49 };
  50 #endif
  51
  52 struct ring {
  53         struct iovec *frames;
  54         uint8_t *mm_space;
  55         size_t mm_len;
  56         struct sockaddr_ll s_ll;
  57         union {
  58                 struct tpacket_req layout;
  59 #ifdef HAVE_TPACKET3
  60                 struct tpacket_req3 layout3;
  61 #endif
  62                 uint8_t raw;
  63         };
  64 };
  65
  66 static inline void next_rnd_slot(unsigned int *it, struct ring *ring)
  67 {
  68         *it = rand() % ring->layout.tp_frame_nr;
  69 }
  70
  71 static inline unsigned int ring_size(char *ifname, unsigned int size)
  72 {
  73         if (size > 0)
  74                 return size;
  75
  76         /*
  77          * Device bitrate in bytes times two as ring size.
  78          *    Fallback => ~    64,00 MB
  79          *     10 MBit => ~     2,38 MB
  80          *     54 MBit => ~    12,88 MB
  81          *    100 MBit => ~    23,84 MB
  82          *    300 MBit => ~    71,52 MB
  83          *  1.000 MBit => ~   238,42 MB
  84          * 10.000 MBit => ~ 2.384.18 MB
  85          */
  86         size = device_bitrate(ifname);
  87         size = (size * 1000000) / 8;
  88         size = size * 2;
  89         if (size == 0)
  90                 size = 1 << 26;
  91
  92         return round_up_cacheline(size);
  93 }
  94
  95 static inline unsigned int ring_frame_size(struct ring *ring)
  96 {
  97         return ring->layout.tp_frame_size;
  98 }
  99
 100 static inline void ring_verify_layout(struct ring *ring)
 101 {
 102         bug_on(ring->layout.tp_block_size  < ring->layout.tp_frame_size);
 103         bug_on((ring->layout.tp_block_size % ring->layout.tp_frame_size) != 0);
 104         bug_on((ring->layout.tp_block_size % getpagesize()) != 0);
 105 }
 106
 107 static inline void tpacket_hdr_clone(struct tpacket2_hdr *thdrd,
 108                                      struct tpacket2_hdr *thdrs)
 109 {
 110         thdrd->tp_sec = thdrs->tp_sec;
 111         thdrd->tp_nsec = thdrs->tp_nsec;
 112         thdrd->tp_snaplen = thdrs->tp_snaplen;
 113         thdrd->tp_len = thdrs->tp_len;
 114 }
 115
 116 static inline void prepare_polling(int sock, struct pollfd *pfd)
 117 {
 118         memset(pfd, 0, sizeof(*pfd));
 119         pfd->fd = sock;
 120         pfd->revents = 0;
 121         pfd->events = POLLIN | POLLRDNORM | POLLERR;
 122 }
 123
 124 static inline void __set_sockopt_tpacket(int sock, int val)
 125 {
 126         int ret = setsockopt(sock, SOL_PACKET, PACKET_VERSION, &val, sizeof(val));
 127         if (ret)
 128                 panic("Cannot set tpacketv2!\n");
 129 }
 130
 131 static inline void set_sockopt_tpacket_v2(int sock)
 132 {
 133         __set_sockopt_tpacket(sock, TPACKET_V2);
 134 }
 135
 136 static inline void set_sockopt_tpacket_v3(int sock)
 137 {
 138 #ifdef HAVE_TPACKET3
 139         __set_sockopt_tpacket(sock, TPACKET_V3);
 140 #endif
 141 }
 142
 143 static inline int get_sockopt_tpacket(int sock)
 144 {
 145         int val, ret;
 146         socklen_t len = sizeof(val);
 147
 148         ret = getsockopt(sock, SOL_PACKET, PACKET_VERSION, &val, &len);
 149         if (ret)
 150                 panic("Cannot get tpacket version!\n");
 151
 152         return val;
 153 }
 154
 155 extern void mmap_ring_generic(int sock, struct ring *ring);
 156 extern void alloc_ring_frames_generic(struct ring *ring, int num, size_t size);
 157 extern void bind_ring_generic(int sock, struct ring *ring, int ifindex, bool tx_only);
 158
 159 #endif /* RING_H */