| /* |
| * This is a module which is used for logging packets. |
| */ |
| |
| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/spinlock.h> |
| #include <linux/skbuff.h> |
| #include <linux/ip.h> |
| #include <net/icmp.h> |
| #include <net/udp.h> |
| #include <net/tcp.h> |
| #include <net/route.h> |
| |
| #include <linux/netfilter.h> |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter_ipv4/ipt_LOG.h> |
| #include <net/netfilter/nf_log.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| MODULE_DESCRIPTION("Xtables: IPv4 packet logging to syslog"); |
| |
| /* Use lock to serialize, so printks don't overlap */ |
| static DEFINE_SPINLOCK(log_lock); |
| |
| /* One level of recursion won't kill us */ |
| static void dump_packet(const struct nf_loginfo *info, |
| const struct sk_buff *skb, |
| unsigned int iphoff) |
| { |
| struct iphdr _iph; |
| const struct iphdr *ih; |
| unsigned int logflags; |
| |
| if (info->type == NF_LOG_TYPE_LOG) |
| logflags = info->u.log.logflags; |
| else |
| logflags = NF_LOG_MASK; |
| |
| ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph); |
| if (ih == NULL) { |
| printk("TRUNCATED"); |
| return; |
| } |
| |
| /* Important fields: |
| * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */ |
| /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */ |
| printk("SRC=%pI4 DST=%pI4 ", |
| &ih->saddr, &ih->daddr); |
| |
| /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */ |
| printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ", |
| ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK, |
| ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id)); |
| |
| /* Max length: 6 "CE DF MF " */ |
| if (ntohs(ih->frag_off) & IP_CE) |
| printk("CE "); |
| if (ntohs(ih->frag_off) & IP_DF) |
| printk("DF "); |
| if (ntohs(ih->frag_off) & IP_MF) |
| printk("MF "); |
| |
| /* Max length: 11 "FRAG:65535 " */ |
| if (ntohs(ih->frag_off) & IP_OFFSET) |
| printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET); |
| |
| if ((logflags & IPT_LOG_IPOPT) |
| && ih->ihl * 4 > sizeof(struct iphdr)) { |
| const unsigned char *op; |
| unsigned char _opt[4 * 15 - sizeof(struct iphdr)]; |
| unsigned int i, optsize; |
| |
| optsize = ih->ihl * 4 - sizeof(struct iphdr); |
| op = skb_header_pointer(skb, iphoff+sizeof(_iph), |
| optsize, _opt); |
| if (op == NULL) { |
| printk("TRUNCATED"); |
| return; |
| } |
| |
| /* Max length: 127 "OPT (" 15*4*2chars ") " */ |
| printk("OPT ("); |
| for (i = 0; i < optsize; i++) |
| printk("%02X", op[i]); |
| printk(") "); |
| } |
| |
| switch (ih->protocol) { |
| case IPPROTO_TCP: { |
| struct tcphdr _tcph; |
| const struct tcphdr *th; |
| |
| /* Max length: 10 "PROTO=TCP " */ |
| printk("PROTO=TCP "); |
| |
| if (ntohs(ih->frag_off) & IP_OFFSET) |
| break; |
| |
| /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| th = skb_header_pointer(skb, iphoff + ih->ihl * 4, |
| sizeof(_tcph), &_tcph); |
| if (th == NULL) { |
| printk("INCOMPLETE [%u bytes] ", |
| skb->len - iphoff - ih->ihl*4); |
| break; |
| } |
| |
| /* Max length: 20 "SPT=65535 DPT=65535 " */ |
| printk("SPT=%u DPT=%u ", |
| ntohs(th->source), ntohs(th->dest)); |
| /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */ |
| if (logflags & IPT_LOG_TCPSEQ) |
| printk("SEQ=%u ACK=%u ", |
| ntohl(th->seq), ntohl(th->ack_seq)); |
| /* Max length: 13 "WINDOW=65535 " */ |
| printk("WINDOW=%u ", ntohs(th->window)); |
| /* Max length: 9 "RES=0x3F " */ |
| printk("RES=0x%02x ", (u8)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22)); |
| /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */ |
| if (th->cwr) |
| printk("CWR "); |
| if (th->ece) |
| printk("ECE "); |
| if (th->urg) |
| printk("URG "); |
| if (th->ack) |
| printk("ACK "); |
| if (th->psh) |
| printk("PSH "); |
| if (th->rst) |
| printk("RST "); |
| if (th->syn) |
| printk("SYN "); |
| if (th->fin) |
| printk("FIN "); |
| /* Max length: 11 "URGP=65535 " */ |
| printk("URGP=%u ", ntohs(th->urg_ptr)); |
| |
| if ((logflags & IPT_LOG_TCPOPT) |
| && th->doff * 4 > sizeof(struct tcphdr)) { |
| unsigned char _opt[4 * 15 - sizeof(struct tcphdr)]; |
| const unsigned char *op; |
| unsigned int i, optsize; |
| |
| optsize = th->doff * 4 - sizeof(struct tcphdr); |
| op = skb_header_pointer(skb, |
| iphoff+ih->ihl*4+sizeof(_tcph), |
| optsize, _opt); |
| if (op == NULL) { |
| printk("TRUNCATED"); |
| return; |
| } |
| |
| /* Max length: 127 "OPT (" 15*4*2chars ") " */ |
| printk("OPT ("); |
| for (i = 0; i < optsize; i++) |
| printk("%02X", op[i]); |
| printk(") "); |
| } |
| break; |
| } |
| case IPPROTO_UDP: |
| case IPPROTO_UDPLITE: { |
| struct udphdr _udph; |
| const struct udphdr *uh; |
| |
| if (ih->protocol == IPPROTO_UDP) |
| /* Max length: 10 "PROTO=UDP " */ |
| printk("PROTO=UDP " ); |
| else /* Max length: 14 "PROTO=UDPLITE " */ |
| printk("PROTO=UDPLITE "); |
| |
| if (ntohs(ih->frag_off) & IP_OFFSET) |
| break; |
| |
| /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| uh = skb_header_pointer(skb, iphoff+ih->ihl*4, |
| sizeof(_udph), &_udph); |
| if (uh == NULL) { |
| printk("INCOMPLETE [%u bytes] ", |
| skb->len - iphoff - ih->ihl*4); |
| break; |
| } |
| |
| /* Max length: 20 "SPT=65535 DPT=65535 " */ |
| printk("SPT=%u DPT=%u LEN=%u ", |
| ntohs(uh->source), ntohs(uh->dest), |
| ntohs(uh->len)); |
| break; |
| } |
| case IPPROTO_ICMP: { |
| struct icmphdr _icmph; |
| const struct icmphdr *ich; |
| static const size_t required_len[NR_ICMP_TYPES+1] |
| = { [ICMP_ECHOREPLY] = 4, |
| [ICMP_DEST_UNREACH] |
| = 8 + sizeof(struct iphdr), |
| [ICMP_SOURCE_QUENCH] |
| = 8 + sizeof(struct iphdr), |
| [ICMP_REDIRECT] |
| = 8 + sizeof(struct iphdr), |
| [ICMP_ECHO] = 4, |
| [ICMP_TIME_EXCEEDED] |
| = 8 + sizeof(struct iphdr), |
| [ICMP_PARAMETERPROB] |
| = 8 + sizeof(struct iphdr), |
| [ICMP_TIMESTAMP] = 20, |
| [ICMP_TIMESTAMPREPLY] = 20, |
| [ICMP_ADDRESS] = 12, |
| [ICMP_ADDRESSREPLY] = 12 }; |
| |
| /* Max length: 11 "PROTO=ICMP " */ |
| printk("PROTO=ICMP "); |
| |
| if (ntohs(ih->frag_off) & IP_OFFSET) |
| break; |
| |
| /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| ich = skb_header_pointer(skb, iphoff + ih->ihl * 4, |
| sizeof(_icmph), &_icmph); |
| if (ich == NULL) { |
| printk("INCOMPLETE [%u bytes] ", |
| skb->len - iphoff - ih->ihl*4); |
| break; |
| } |
| |
| /* Max length: 18 "TYPE=255 CODE=255 " */ |
| printk("TYPE=%u CODE=%u ", ich->type, ich->code); |
| |
| /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| if (ich->type <= NR_ICMP_TYPES |
| && required_len[ich->type] |
| && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) { |
| printk("INCOMPLETE [%u bytes] ", |
| skb->len - iphoff - ih->ihl*4); |
| break; |
| } |
| |
| switch (ich->type) { |
| case ICMP_ECHOREPLY: |
| case ICMP_ECHO: |
| /* Max length: 19 "ID=65535 SEQ=65535 " */ |
| printk("ID=%u SEQ=%u ", |
| ntohs(ich->un.echo.id), |
| ntohs(ich->un.echo.sequence)); |
| break; |
| |
| case ICMP_PARAMETERPROB: |
| /* Max length: 14 "PARAMETER=255 " */ |
| printk("PARAMETER=%u ", |
| ntohl(ich->un.gateway) >> 24); |
| break; |
| case ICMP_REDIRECT: |
| /* Max length: 24 "GATEWAY=255.255.255.255 " */ |
| printk("GATEWAY=%pI4 ", &ich->un.gateway); |
| /* Fall through */ |
| case ICMP_DEST_UNREACH: |
| case ICMP_SOURCE_QUENCH: |
| case ICMP_TIME_EXCEEDED: |
| /* Max length: 3+maxlen */ |
| if (!iphoff) { /* Only recurse once. */ |
| printk("["); |
| dump_packet(info, skb, |
| iphoff + ih->ihl*4+sizeof(_icmph)); |
| printk("] "); |
| } |
| |
| /* Max length: 10 "MTU=65535 " */ |
| if (ich->type == ICMP_DEST_UNREACH |
| && ich->code == ICMP_FRAG_NEEDED) |
| printk("MTU=%u ", ntohs(ich->un.frag.mtu)); |
| } |
| break; |
| } |
| /* Max Length */ |
| case IPPROTO_AH: { |
| struct ip_auth_hdr _ahdr; |
| const struct ip_auth_hdr *ah; |
| |
| if (ntohs(ih->frag_off) & IP_OFFSET) |
| break; |
| |
| /* Max length: 9 "PROTO=AH " */ |
| printk("PROTO=AH "); |
| |
| /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| ah = skb_header_pointer(skb, iphoff+ih->ihl*4, |
| sizeof(_ahdr), &_ahdr); |
| if (ah == NULL) { |
| printk("INCOMPLETE [%u bytes] ", |
| skb->len - iphoff - ih->ihl*4); |
| break; |
| } |
| |
| /* Length: 15 "SPI=0xF1234567 " */ |
| printk("SPI=0x%x ", ntohl(ah->spi)); |
| break; |
| } |
| case IPPROTO_ESP: { |
| struct ip_esp_hdr _esph; |
| const struct ip_esp_hdr *eh; |
| |
| /* Max length: 10 "PROTO=ESP " */ |
| printk("PROTO=ESP "); |
| |
| if (ntohs(ih->frag_off) & IP_OFFSET) |
| break; |
| |
| /* Max length: 25 "INCOMPLETE [65535 bytes] " */ |
| eh = skb_header_pointer(skb, iphoff+ih->ihl*4, |
| sizeof(_esph), &_esph); |
| if (eh == NULL) { |
| printk("INCOMPLETE [%u bytes] ", |
| skb->len - iphoff - ih->ihl*4); |
| break; |
| } |
| |
| /* Length: 15 "SPI=0xF1234567 " */ |
| printk("SPI=0x%x ", ntohl(eh->spi)); |
| break; |
| } |
| /* Max length: 10 "PROTO 255 " */ |
| default: |
| printk("PROTO=%u ", ih->protocol); |
| } |
| |
| /* Max length: 15 "UID=4294967295 " */ |
| if ((logflags & IPT_LOG_UID) && !iphoff && skb->sk) { |
| read_lock_bh(&skb->sk->sk_callback_lock); |
| if (skb->sk->sk_socket && skb->sk->sk_socket->file) |
| printk("UID=%u GID=%u ", |
| skb->sk->sk_socket->file->f_cred->fsuid, |
| skb->sk->sk_socket->file->f_cred->fsgid); |
| read_unlock_bh(&skb->sk->sk_callback_lock); |
| } |
| |
| /* Max length: 16 "MARK=0xFFFFFFFF " */ |
| if (!iphoff && skb->mark) |
| printk("MARK=0x%x ", skb->mark); |
| |
| /* Proto Max log string length */ |
| /* IP: 40+46+6+11+127 = 230 */ |
| /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */ |
| /* UDP: 10+max(25,20) = 35 */ |
| /* UDPLITE: 14+max(25,20) = 39 */ |
| /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */ |
| /* ESP: 10+max(25)+15 = 50 */ |
| /* AH: 9+max(25)+15 = 49 */ |
| /* unknown: 10 */ |
| |
| /* (ICMP allows recursion one level deep) */ |
| /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */ |
| /* maxlen = 230+ 91 + 230 + 252 = 803 */ |
| } |
| |
| static struct nf_loginfo default_loginfo = { |
| .type = NF_LOG_TYPE_LOG, |
| .u = { |
| .log = { |
| .level = 0, |
| .logflags = NF_LOG_MASK, |
| }, |
| }, |
| }; |
| |
| static void |
| ipt_log_packet(u_int8_t pf, |
| unsigned int hooknum, |
| const struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| const struct nf_loginfo *loginfo, |
| const char *prefix) |
| { |
| if (!loginfo) |
| loginfo = &default_loginfo; |
| |
| spin_lock_bh(&log_lock); |
| printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level, |
| prefix, |
| in ? in->name : "", |
| out ? out->name : ""); |
| #ifdef CONFIG_BRIDGE_NETFILTER |
| if (skb->nf_bridge) { |
| const struct net_device *physindev; |
| const struct net_device *physoutdev; |
| |
| physindev = skb->nf_bridge->physindev; |
| if (physindev && in != physindev) |
| printk("PHYSIN=%s ", physindev->name); |
| physoutdev = skb->nf_bridge->physoutdev; |
| if (physoutdev && out != physoutdev) |
| printk("PHYSOUT=%s ", physoutdev->name); |
| } |
| #endif |
| |
| if (in && !out) { |
| /* MAC logging for input chain only. */ |
| printk("MAC="); |
| if (skb->dev && skb->dev->hard_header_len |
| && skb->mac_header != skb->network_header) { |
| int i; |
| const unsigned char *p = skb_mac_header(skb); |
| for (i = 0; i < skb->dev->hard_header_len; i++,p++) |
| printk("%02x%c", *p, |
| i==skb->dev->hard_header_len - 1 |
| ? ' ':':'); |
| } else |
| printk(" "); |
| } |
| |
| dump_packet(loginfo, skb, 0); |
| printk("\n"); |
| spin_unlock_bh(&log_lock); |
| } |
| |
| static unsigned int |
| log_tg(struct sk_buff *skb, const struct xt_target_param *par) |
| { |
| const struct ipt_log_info *loginfo = par->targinfo; |
| struct nf_loginfo li; |
| |
| li.type = NF_LOG_TYPE_LOG; |
| li.u.log.level = loginfo->level; |
| li.u.log.logflags = loginfo->logflags; |
| |
| ipt_log_packet(NFPROTO_IPV4, par->hooknum, skb, par->in, par->out, &li, |
| loginfo->prefix); |
| return XT_CONTINUE; |
| } |
| |
| static bool log_tg_check(const struct xt_tgchk_param *par) |
| { |
| const struct ipt_log_info *loginfo = par->targinfo; |
| |
| if (loginfo->level >= 8) { |
| pr_debug("LOG: level %u >= 8\n", loginfo->level); |
| return false; |
| } |
| if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') { |
| pr_debug("LOG: prefix term %i\n", |
| loginfo->prefix[sizeof(loginfo->prefix)-1]); |
| return false; |
| } |
| return true; |
| } |
| |
| static struct xt_target log_tg_reg __read_mostly = { |
| .name = "LOG", |
| .family = NFPROTO_IPV4, |
| .target = log_tg, |
| .targetsize = sizeof(struct ipt_log_info), |
| .checkentry = log_tg_check, |
| .me = THIS_MODULE, |
| }; |
| |
| static struct nf_logger ipt_log_logger __read_mostly = { |
| .name = "ipt_LOG", |
| .logfn = &ipt_log_packet, |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init log_tg_init(void) |
| { |
| int ret; |
| |
| ret = xt_register_target(&log_tg_reg); |
| if (ret < 0) |
| return ret; |
| nf_log_register(NFPROTO_IPV4, &ipt_log_logger); |
| return 0; |
| } |
| |
| static void __exit log_tg_exit(void) |
| { |
| nf_log_unregister(&ipt_log_logger); |
| xt_unregister_target(&log_tg_reg); |
| } |
| |
| module_init(log_tg_init); |
| module_exit(log_tg_exit); |