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 #ifndef POLLRDNORM
  30 # define POLLRDNORM     0x0040
  31 #endif
  32
  33 union tpacket_uhdr {
  34         struct tpacket_hdr  *h1;
  35         struct tpacket2_hdr *h2;
  36 #ifdef HAVE_TPACKET3
  37         struct tpacket3_hdr *h3;
  38 #endif
  39         void *raw;
  40 };
  41
  42 #ifdef HAVE_TPACKET3
  43 #define tpacket_uhdr(hdr, member, v3)   \
  44         ((v3) ? ((hdr).h3)->member : ((hdr).h2)->member)
  45 #else
  46 #define tpacket_uhdr(hdr, member, v3)   \
  47         (((hdr).h2)->member)
  48 #endif /* HAVE_TPACKET3 */
  49
  50 struct frame_map {
  51         struct tpacket2_hdr tp_h __aligned_tpacket;
  52         struct sockaddr_ll s_ll __align_tpacket(sizeof(struct tpacket2_hdr));
  53 };
  54
  55 #ifdef HAVE_TPACKET3
  56 struct block_desc {
  57         uint32_t version;
  58         uint32_t offset_to_priv;
  59         struct tpacket_hdr_v1 h1;
  60 };
  61 #endif
  62
  63 struct ring {
  64         struct iovec *frames;
  65         uint8_t *mm_space;
  66         size_t mm_len;
  67         struct sockaddr_ll s_ll;
  68         union {
  69                 struct tpacket_req layout;
  70 #ifdef HAVE_TPACKET3
  71                 struct tpacket_req3 layout3;
  72 #endif
  73                 uint8_t raw;
  74         };
  75 };
  76
  77 static inline void next_rnd_slot(unsigned int *it, struct ring *ring)
  78 {
  79         *it = rand() % ring->layout.tp_frame_nr;
  80 }
  81
  82 static inline size_t ring_size(const char *ifname, size_t size)
  83 {
  84         if (size > 0)
  85                 return size;
  86
  87         /*
  88          * Device bitrate in bytes times two as ring size.
  89          *    Fallback => ~    64,00 MB
  90          *     10 MBit => ~     2,38 MB
  91          *     54 MBit => ~    12,88 MB
  92          *    100 MBit => ~    23,84 MB
  93          *    300 MBit => ~    71,52 MB
  94          *  1.000 MBit => ~   238,42 MB
  95          * 10.000 MBit => ~ 2.384.18 MB
  96          */
  97         size = device_bitrate(ifname);
  98         size = (size * 1000000) / 8;
  99         size = size * 2;
 100         if (size == 0)
 101                 size = 1 << 26;
 102
 103         return round_up_cacheline(size);
 104 }
 105
 106 static inline unsigned int ring_frame_size(struct ring *ring)
 107 {
 108         return ring->layout.tp_frame_size;
 109 }
 110
 111 static inline void ring_verify_layout(struct ring *ring)
 112 {
 113         bug_on(ring->layout.tp_block_size  < ring->layout.tp_frame_size);
 114         bug_on((ring->layout.tp_block_size % ring->layout.tp_frame_size) != 0);
 115         bug_on((ring->layout.tp_block_size % RUNTIME_PAGE_SIZE) != 0);
 116 }
 117
 118 static inline void tpacket_hdr_clone(struct tpacket2_hdr *thdrd,
 119                                      struct tpacket2_hdr *thdrs)
 120 {
 121         thdrd->tp_sec = thdrs->tp_sec;
 122         thdrd->tp_nsec = thdrs->tp_nsec;
 123         thdrd->tp_snaplen = thdrs->tp_snaplen;
 124         thdrd->tp_len = thdrs->tp_len;
 125 }
 126
 127 static inline void prepare_polling(int sock, struct pollfd *pfd)
 128 {
 129         memset(pfd, 0, sizeof(*pfd));
 130         pfd->fd = sock;
 131         pfd->revents = 0;
 132         pfd->events = POLLIN | POLLRDNORM | POLLERR;
 133 }
 134
 135 static inline void __set_sockopt_tpacket(int sock, int val)
 136 {
 137         int ret = setsockopt(sock, SOL_PACKET, PACKET_VERSION, &val, sizeof(val));
 138         if (ret)
 139                 panic("Cannot set tpacketv2!\n");
 140 }
 141
 142 static inline void set_sockopt_tpacket_v2(int sock)
 143 {
 144         __set_sockopt_tpacket(sock, TPACKET_V2);
 145 }
 146
 147 #ifdef HAVE_TPACKET3
 148 static inline void set_sockopt_tpacket_v3(int sock)
 149 {
 150         __set_sockopt_tpacket(sock, TPACKET_V3);
 151 }
 152 #else
 153 static inline void set_sockopt_tpacket_v3(int sock __maybe_unused)
 154 {
 155 }
 156 #endif
 157
 158 static inline int get_sockopt_tpacket(int sock)
 159 {
 160         int val, ret;
 161         socklen_t len = sizeof(val);
 162
 163         ret = getsockopt(sock, SOL_PACKET, PACKET_VERSION, &val, &len);
 164         if (ret)
 165                 panic("Cannot get tpacket version!\n");
 166
 167         return val;
 168 }
 169
 170 extern void mmap_ring_generic(int sock, struct ring *ring);
 171 extern void alloc_ring_frames_generic(struct ring *ring, int num, size_t size);
 172 extern void bind_ring_generic(int sock, struct ring *ring, int ifindex, bool tx_only);
 173
 174 #endif /* RING_H */