![Eric Dumazet](/assets/img/avatar_default.png)
ipt_LOG & ip6t_LOG use lot of calls to printk() and use a lock in a hope several cpus wont mix their output in syslog. printk() being very expensive [1], its better to call it once, on a prebuilt and complete line. Also, with mixed IPv4 and IPv6 trafic, separate IPv4/IPv6 locks dont avoid garbage. I used an allocation of a 1024 bytes structure, sort of seq_printf() but with a fixed size limit. Use a static buffer if dynamic allocation failed. Emit a once time alert if buffer size happens to be too short. [1]: printk() has various features like printk_delay()... Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Patrick McHardy <kaber@trash.net>
529 lines
12 KiB
C
529 lines
12 KiB
C
/*
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* This is a module which is used for logging packets.
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*/
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/* (C) 2001 Jan Rekorajski <baggins@pld.org.pl>
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/if_arp.h>
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#include <linux/ip.h>
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#include <linux/spinlock.h>
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#include <linux/icmpv6.h>
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#include <net/udp.h>
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#include <net/tcp.h>
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#include <net/ipv6.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <net/netfilter/nf_log.h>
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#include <net/netfilter/xt_log.h>
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MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
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MODULE_DESCRIPTION("Xtables: IPv6 packet logging to syslog");
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MODULE_LICENSE("GPL");
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struct in_device;
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#include <net/route.h>
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#include <linux/netfilter_ipv6/ip6t_LOG.h>
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/* One level of recursion won't kill us */
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static void dump_packet(struct sbuff *m,
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const struct nf_loginfo *info,
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const struct sk_buff *skb, unsigned int ip6hoff,
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int recurse)
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{
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u_int8_t currenthdr;
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int fragment;
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struct ipv6hdr _ip6h;
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const struct ipv6hdr *ih;
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unsigned int ptr;
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unsigned int hdrlen = 0;
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unsigned int logflags;
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if (info->type == NF_LOG_TYPE_LOG)
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logflags = info->u.log.logflags;
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else
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logflags = NF_LOG_MASK;
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ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
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if (ih == NULL) {
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sb_add(m, "TRUNCATED");
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return;
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}
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/* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
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sb_add(m, "SRC=%pI6 DST=%pI6 ", &ih->saddr, &ih->daddr);
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/* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
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sb_add(m, "LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
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ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
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(ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
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ih->hop_limit,
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(ntohl(*(__be32 *)ih) & 0x000fffff));
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fragment = 0;
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ptr = ip6hoff + sizeof(struct ipv6hdr);
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currenthdr = ih->nexthdr;
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while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
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struct ipv6_opt_hdr _hdr;
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const struct ipv6_opt_hdr *hp;
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hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
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if (hp == NULL) {
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sb_add(m, "TRUNCATED");
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return;
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}
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/* Max length: 48 "OPT (...) " */
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if (logflags & IP6T_LOG_IPOPT)
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sb_add(m, "OPT ( ");
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switch (currenthdr) {
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case IPPROTO_FRAGMENT: {
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struct frag_hdr _fhdr;
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const struct frag_hdr *fh;
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sb_add(m, "FRAG:");
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fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
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&_fhdr);
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if (fh == NULL) {
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sb_add(m, "TRUNCATED ");
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return;
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}
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/* Max length: 6 "65535 " */
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sb_add(m, "%u ", ntohs(fh->frag_off) & 0xFFF8);
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/* Max length: 11 "INCOMPLETE " */
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if (fh->frag_off & htons(0x0001))
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sb_add(m, "INCOMPLETE ");
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sb_add(m, "ID:%08x ", ntohl(fh->identification));
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if (ntohs(fh->frag_off) & 0xFFF8)
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fragment = 1;
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hdrlen = 8;
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break;
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}
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case IPPROTO_DSTOPTS:
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case IPPROTO_ROUTING:
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case IPPROTO_HOPOPTS:
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if (fragment) {
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if (logflags & IP6T_LOG_IPOPT)
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sb_add(m, ")");
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return;
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}
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hdrlen = ipv6_optlen(hp);
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break;
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/* Max Length */
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case IPPROTO_AH:
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if (logflags & IP6T_LOG_IPOPT) {
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struct ip_auth_hdr _ahdr;
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const struct ip_auth_hdr *ah;
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/* Max length: 3 "AH " */
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sb_add(m, "AH ");
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if (fragment) {
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sb_add(m, ")");
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return;
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}
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ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
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&_ahdr);
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if (ah == NULL) {
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/*
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* Max length: 26 "INCOMPLETE [65535
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* bytes] )"
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*/
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sb_add(m, "INCOMPLETE [%u bytes] )",
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skb->len - ptr);
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return;
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}
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/* Length: 15 "SPI=0xF1234567 */
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sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
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}
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hdrlen = (hp->hdrlen+2)<<2;
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break;
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case IPPROTO_ESP:
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if (logflags & IP6T_LOG_IPOPT) {
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struct ip_esp_hdr _esph;
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const struct ip_esp_hdr *eh;
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/* Max length: 4 "ESP " */
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sb_add(m, "ESP ");
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if (fragment) {
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sb_add(m, ")");
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return;
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}
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/*
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* Max length: 26 "INCOMPLETE [65535 bytes] )"
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*/
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eh = skb_header_pointer(skb, ptr, sizeof(_esph),
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&_esph);
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if (eh == NULL) {
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sb_add(m, "INCOMPLETE [%u bytes] )",
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skb->len - ptr);
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return;
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}
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/* Length: 16 "SPI=0xF1234567 )" */
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sb_add(m, "SPI=0x%x )", ntohl(eh->spi) );
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}
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return;
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default:
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/* Max length: 20 "Unknown Ext Hdr 255" */
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sb_add(m, "Unknown Ext Hdr %u", currenthdr);
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return;
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}
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if (logflags & IP6T_LOG_IPOPT)
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sb_add(m, ") ");
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currenthdr = hp->nexthdr;
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ptr += hdrlen;
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}
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switch (currenthdr) {
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case IPPROTO_TCP: {
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struct tcphdr _tcph;
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const struct tcphdr *th;
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/* Max length: 10 "PROTO=TCP " */
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sb_add(m, "PROTO=TCP ");
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if (fragment)
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break;
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/* Max length: 25 "INCOMPLETE [65535 bytes] " */
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th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
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if (th == NULL) {
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sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
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return;
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}
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/* Max length: 20 "SPT=65535 DPT=65535 " */
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sb_add(m, "SPT=%u DPT=%u ",
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ntohs(th->source), ntohs(th->dest));
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/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
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if (logflags & IP6T_LOG_TCPSEQ)
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sb_add(m, "SEQ=%u ACK=%u ",
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ntohl(th->seq), ntohl(th->ack_seq));
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/* Max length: 13 "WINDOW=65535 " */
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sb_add(m, "WINDOW=%u ", ntohs(th->window));
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/* Max length: 9 "RES=0x3C " */
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sb_add(m, "RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
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/* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
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if (th->cwr)
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sb_add(m, "CWR ");
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if (th->ece)
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sb_add(m, "ECE ");
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if (th->urg)
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sb_add(m, "URG ");
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if (th->ack)
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sb_add(m, "ACK ");
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if (th->psh)
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sb_add(m, "PSH ");
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if (th->rst)
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sb_add(m, "RST ");
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if (th->syn)
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sb_add(m, "SYN ");
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if (th->fin)
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sb_add(m, "FIN ");
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/* Max length: 11 "URGP=65535 " */
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sb_add(m, "URGP=%u ", ntohs(th->urg_ptr));
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if ((logflags & IP6T_LOG_TCPOPT) &&
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th->doff * 4 > sizeof(struct tcphdr)) {
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u_int8_t _opt[60 - sizeof(struct tcphdr)];
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const u_int8_t *op;
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unsigned int i;
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unsigned int optsize = th->doff * 4
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- sizeof(struct tcphdr);
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op = skb_header_pointer(skb,
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ptr + sizeof(struct tcphdr),
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optsize, _opt);
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if (op == NULL) {
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sb_add(m, "OPT (TRUNCATED)");
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return;
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}
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/* Max length: 127 "OPT (" 15*4*2chars ") " */
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sb_add(m, "OPT (");
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for (i =0; i < optsize; i++)
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sb_add(m, "%02X", op[i]);
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sb_add(m, ") ");
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}
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break;
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}
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case IPPROTO_UDP:
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case IPPROTO_UDPLITE: {
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struct udphdr _udph;
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const struct udphdr *uh;
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if (currenthdr == IPPROTO_UDP)
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/* Max length: 10 "PROTO=UDP " */
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sb_add(m, "PROTO=UDP " );
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else /* Max length: 14 "PROTO=UDPLITE " */
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sb_add(m, "PROTO=UDPLITE ");
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if (fragment)
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break;
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/* Max length: 25 "INCOMPLETE [65535 bytes] " */
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uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
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if (uh == NULL) {
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sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
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return;
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}
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/* Max length: 20 "SPT=65535 DPT=65535 " */
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sb_add(m, "SPT=%u DPT=%u LEN=%u ",
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ntohs(uh->source), ntohs(uh->dest),
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ntohs(uh->len));
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break;
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}
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case IPPROTO_ICMPV6: {
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struct icmp6hdr _icmp6h;
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const struct icmp6hdr *ic;
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/* Max length: 13 "PROTO=ICMPv6 " */
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sb_add(m, "PROTO=ICMPv6 ");
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if (fragment)
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break;
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/* Max length: 25 "INCOMPLETE [65535 bytes] " */
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ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
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if (ic == NULL) {
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sb_add(m, "INCOMPLETE [%u bytes] ", skb->len - ptr);
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return;
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}
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/* Max length: 18 "TYPE=255 CODE=255 " */
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sb_add(m, "TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
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switch (ic->icmp6_type) {
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case ICMPV6_ECHO_REQUEST:
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case ICMPV6_ECHO_REPLY:
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/* Max length: 19 "ID=65535 SEQ=65535 " */
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sb_add(m, "ID=%u SEQ=%u ",
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ntohs(ic->icmp6_identifier),
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ntohs(ic->icmp6_sequence));
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break;
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case ICMPV6_MGM_QUERY:
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case ICMPV6_MGM_REPORT:
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case ICMPV6_MGM_REDUCTION:
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break;
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case ICMPV6_PARAMPROB:
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/* Max length: 17 "POINTER=ffffffff " */
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sb_add(m, "POINTER=%08x ", ntohl(ic->icmp6_pointer));
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/* Fall through */
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case ICMPV6_DEST_UNREACH:
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case ICMPV6_PKT_TOOBIG:
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case ICMPV6_TIME_EXCEED:
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/* Max length: 3+maxlen */
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if (recurse) {
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sb_add(m, "[");
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dump_packet(m, info, skb,
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ptr + sizeof(_icmp6h), 0);
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sb_add(m, "] ");
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}
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/* Max length: 10 "MTU=65535 " */
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if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
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sb_add(m, "MTU=%u ", ntohl(ic->icmp6_mtu));
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}
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break;
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}
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/* Max length: 10 "PROTO=255 " */
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default:
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sb_add(m, "PROTO=%u ", currenthdr);
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}
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/* Max length: 15 "UID=4294967295 " */
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if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
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read_lock_bh(&skb->sk->sk_callback_lock);
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if (skb->sk->sk_socket && skb->sk->sk_socket->file)
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sb_add(m, "UID=%u GID=%u ",
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skb->sk->sk_socket->file->f_cred->fsuid,
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skb->sk->sk_socket->file->f_cred->fsgid);
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read_unlock_bh(&skb->sk->sk_callback_lock);
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}
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/* Max length: 16 "MARK=0xFFFFFFFF " */
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if (!recurse && skb->mark)
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sb_add(m, "MARK=0x%x ", skb->mark);
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}
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static void dump_mac_header(struct sbuff *m,
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const struct nf_loginfo *info,
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const struct sk_buff *skb)
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{
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struct net_device *dev = skb->dev;
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unsigned int logflags = 0;
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if (info->type == NF_LOG_TYPE_LOG)
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logflags = info->u.log.logflags;
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if (!(logflags & IP6T_LOG_MACDECODE))
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goto fallback;
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switch (dev->type) {
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case ARPHRD_ETHER:
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sb_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
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eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
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ntohs(eth_hdr(skb)->h_proto));
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return;
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default:
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break;
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}
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fallback:
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sb_add(m, "MAC=");
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if (dev->hard_header_len &&
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skb->mac_header != skb->network_header) {
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const unsigned char *p = skb_mac_header(skb);
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unsigned int len = dev->hard_header_len;
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unsigned int i;
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if (dev->type == ARPHRD_SIT &&
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(p -= ETH_HLEN) < skb->head)
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p = NULL;
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if (p != NULL) {
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sb_add(m, "%02x", *p++);
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for (i = 1; i < len; i++)
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sb_add(m, ":%02x", p[i]);
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}
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sb_add(m, " ");
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if (dev->type == ARPHRD_SIT) {
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const struct iphdr *iph =
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(struct iphdr *)skb_mac_header(skb);
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sb_add(m, "TUNNEL=%pI4->%pI4 ", &iph->saddr, &iph->daddr);
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}
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} else
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sb_add(m, " ");
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}
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static struct nf_loginfo default_loginfo = {
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.type = NF_LOG_TYPE_LOG,
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.u = {
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.log = {
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.level = 5,
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.logflags = NF_LOG_MASK,
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},
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},
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};
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static void
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ip6t_log_packet(u_int8_t pf,
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unsigned int hooknum,
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const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const struct nf_loginfo *loginfo,
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const char *prefix)
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{
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struct sbuff *m = sb_open();
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if (!loginfo)
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loginfo = &default_loginfo;
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sb_add(m, "<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
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prefix,
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in ? in->name : "",
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out ? out->name : "");
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/* MAC logging for input path only. */
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if (in && !out)
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dump_mac_header(m, loginfo, skb);
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dump_packet(m, loginfo, skb, skb_network_offset(skb), 1);
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sb_close(m);
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}
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static unsigned int
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log_tg6(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct ip6t_log_info *loginfo = par->targinfo;
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struct nf_loginfo li;
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li.type = NF_LOG_TYPE_LOG;
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li.u.log.level = loginfo->level;
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li.u.log.logflags = loginfo->logflags;
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ip6t_log_packet(NFPROTO_IPV6, par->hooknum, skb, par->in, par->out,
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&li, loginfo->prefix);
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return XT_CONTINUE;
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}
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static int log_tg6_check(const struct xt_tgchk_param *par)
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{
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const struct ip6t_log_info *loginfo = par->targinfo;
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if (loginfo->level >= 8) {
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pr_debug("level %u >= 8\n", loginfo->level);
|
|
return -EINVAL;
|
|
}
|
|
if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
|
|
pr_debug("prefix not null-terminated\n");
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static struct xt_target log_tg6_reg __read_mostly = {
|
|
.name = "LOG",
|
|
.family = NFPROTO_IPV6,
|
|
.target = log_tg6,
|
|
.targetsize = sizeof(struct ip6t_log_info),
|
|
.checkentry = log_tg6_check,
|
|
.me = THIS_MODULE,
|
|
};
|
|
|
|
static struct nf_logger ip6t_logger __read_mostly = {
|
|
.name = "ip6t_LOG",
|
|
.logfn = &ip6t_log_packet,
|
|
.me = THIS_MODULE,
|
|
};
|
|
|
|
static int __init log_tg6_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = xt_register_target(&log_tg6_reg);
|
|
if (ret < 0)
|
|
return ret;
|
|
nf_log_register(NFPROTO_IPV6, &ip6t_logger);
|
|
return 0;
|
|
}
|
|
|
|
static void __exit log_tg6_exit(void)
|
|
{
|
|
nf_log_unregister(&ip6t_logger);
|
|
xt_unregister_target(&log_tg6_reg);
|
|
}
|
|
|
|
module_init(log_tg6_init);
|
|
module_exit(log_tg6_exit);
|