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