LXR linux/net/netfilter/nf_log

   1/* (C) 1999-2001 Paul `Rusty' Russell
   2 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/spinlock.h>
  11#include <linux/skbuff.h>
  12#include <linux/if_arp.h>
  13#include <linux/ip.h>
  14#include <net/icmp.h>
  15#include <net/udp.h>
  16#include <net/tcp.h>
  17#include <net/route.h>
  18
  19#include <linux/netfilter.h>
  20#include <linux/netfilter/xt_LOG.h>
  21#include <net/netfilter/nf_log.h>
  22
  23int nf_log_dump_udp_header(struct nf_log_buf *m, const struct sk_buff *skb,
  24                           u8 proto, int fragment, unsigned int offset)
  25{
  26        struct udphdr _udph;
  27        const struct udphdr *uh;
  28
  29        if (proto == IPPROTO_UDP)
  30                /* Max length: 10 "PROTO=UDP "     */
  31                nf_log_buf_add(m, "PROTO=UDP ");
  32        else    /* Max length: 14 "PROTO=UDPLITE " */
  33                nf_log_buf_add(m, "PROTO=UDPLITE ");
  34
  35        if (fragment)
  36                goto out;
  37
  38        /* Max length: 25 "INCOMPLETE [65535 bytes] " */
  39        uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
  40        if (uh == NULL) {
  41                nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
  42
  43                return 1;
  44        }
  45
  46        /* Max length: 20 "SPT=65535 DPT=65535 " */
  47        nf_log_buf_add(m, "SPT=%u DPT=%u LEN=%u ",
  48                       ntohs(uh->source), ntohs(uh->dest), ntohs(uh->len));
  49
  50out:
  51        return 0;
  52}
  53EXPORT_SYMBOL_GPL(nf_log_dump_udp_header);
  54
  55int nf_log_dump_tcp_header(struct nf_log_buf *m, const struct sk_buff *skb,
  56                           u8 proto, int fragment, unsigned int offset,
  57                           unsigned int logflags)
  58{
  59        struct tcphdr _tcph;
  60        const struct tcphdr *th;
  61
  62        /* Max length: 10 "PROTO=TCP " */
  63        nf_log_buf_add(m, "PROTO=TCP ");
  64
  65        if (fragment)
  66                return 0;
  67
  68        /* Max length: 25 "INCOMPLETE [65535 bytes] " */
  69        th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
  70        if (th == NULL) {
  71                nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
  72                return 1;
  73        }
  74
  75        /* Max length: 20 "SPT=65535 DPT=65535 " */
  76        nf_log_buf_add(m, "SPT=%u DPT=%u ",
  77                       ntohs(th->source), ntohs(th->dest));
  78        /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
  79        if (logflags & XT_LOG_TCPSEQ) {
  80                nf_log_buf_add(m, "SEQ=%u ACK=%u ",
  81                               ntohl(th->seq), ntohl(th->ack_seq));
  82        }
  83
  84        /* Max length: 13 "WINDOW=65535 " */
  85        nf_log_buf_add(m, "WINDOW=%u ", ntohs(th->window));
  86        /* Max length: 9 "RES=0x3C " */
  87        nf_log_buf_add(m, "RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) &
  88                                            TCP_RESERVED_BITS) >> 22));
  89        /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
  90        if (th->cwr)
  91                nf_log_buf_add(m, "CWR ");
  92        if (th->ece)
  93                nf_log_buf_add(m, "ECE ");
  94        if (th->urg)
  95                nf_log_buf_add(m, "URG ");
  96        if (th->ack)
  97                nf_log_buf_add(m, "ACK ");
  98        if (th->psh)
  99                nf_log_buf_add(m, "PSH ");
 100        if (th->rst)
 101                nf_log_buf_add(m, "RST ");
 102        if (th->syn)
 103                nf_log_buf_add(m, "SYN ");
 104        if (th->fin)
 105                nf_log_buf_add(m, "FIN ");
 106        /* Max length: 11 "URGP=65535 " */
 107        nf_log_buf_add(m, "URGP=%u ", ntohs(th->urg_ptr));
 108
 109        if ((logflags & XT_LOG_TCPOPT) && th->doff*4 > sizeof(struct tcphdr)) {
 110                u_int8_t _opt[60 - sizeof(struct tcphdr)];
 111                const u_int8_t *op;
 112                unsigned int i;
 113                unsigned int optsize = th->doff*4 - sizeof(struct tcphdr);
 114
 115                op = skb_header_pointer(skb, offset + sizeof(struct tcphdr),
 116                                        optsize, _opt);
 117                if (op == NULL) {
 118                        nf_log_buf_add(m, "OPT (TRUNCATED)");
 119                        return 1;
 120                }
 121
 122                /* Max length: 127 "OPT (" 15*4*2chars ") " */
 123                nf_log_buf_add(m, "OPT (");
 124                for (i = 0; i < optsize; i++)
 125                        nf_log_buf_add(m, "%02X", op[i]);
 126
 127                nf_log_buf_add(m, ") ");
 128        }
 129
 130        return 0;
 131}
 132EXPORT_SYMBOL_GPL(nf_log_dump_tcp_header);
 133
 134void nf_log_dump_sk_uid_gid(struct nf_log_buf *m, struct sock *sk)
 135{
 136        if (!sk || sk->sk_state == TCP_TIME_WAIT)
 137                return;
 138
 139        read_lock_bh(&sk->sk_callback_lock);
 140        if (sk->sk_socket && sk->sk_socket->file) {
 141                const struct cred *cred = sk->sk_socket->file->f_cred;
 142                nf_log_buf_add(m, "UID=%u GID=%u ",
 143                        from_kuid_munged(&init_user_ns, cred->fsuid),
 144                        from_kgid_munged(&init_user_ns, cred->fsgid));
 145        }
 146        read_unlock_bh(&sk->sk_callback_lock);
 147}
 148EXPORT_SYMBOL_GPL(nf_log_dump_sk_uid_gid);
 149
 150void
 151nf_log_dump_packet_common(struct nf_log_buf *m, u_int8_t pf,
 152                          unsigned int hooknum, const struct sk_buff *skb,
 153                          const struct net_device *in,
 154                          const struct net_device *out,
 155                          const struct nf_loginfo *loginfo, const char *prefix)
 156{
 157        nf_log_buf_add(m, KERN_SOH "%c%sIN=%s OUT=%s ",
 158               '0' + loginfo->u.log.level, prefix,
 159               in ? in->name : "",
 160               out ? out->name : "");
 161#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 162        if (skb->nf_bridge) {
 163                const struct net_device *physindev;
 164                const struct net_device *physoutdev;
 165
 166                physindev = skb->nf_bridge->physindev;
 167                if (physindev && in != physindev)
 168                        nf_log_buf_add(m, "PHYSIN=%s ", physindev->name);
 169                physoutdev = skb->nf_bridge->physoutdev;
 170                if (physoutdev && out != physoutdev)
 171                        nf_log_buf_add(m, "PHYSOUT=%s ", physoutdev->name);
 172        }
 173#endif
 174}
 175EXPORT_SYMBOL_GPL(nf_log_dump_packet_common);
 176
 177static int __init nf_log_common_init(void)
 178{
 179        return 0;
 180}
 181
 182static void __exit nf_log_common_exit(void) {}
 183
 184module_init(nf_log_common_init);
 185module_exit(nf_log_common_exit);
 186
 187MODULE_LICENSE("GPL");
 188