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