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_bridge.h>
21#include <linux/netfilter/xt_LOG.h>
22#include <net/netfilter/nf_log.h>
23
24int nf_log_dump_udp_header(struct nf_log_buf *m, const struct sk_buff *skb,
25			   u8 proto, int fragment, unsigned int offset)
26{
27	struct udphdr _udph;
28	const struct udphdr *uh;
29
30	if (proto == IPPROTO_UDP)
31		/* Max length: 10 "PROTO=UDP "     */
32		nf_log_buf_add(m, "PROTO=UDP ");
33	else	/* Max length: 14 "PROTO=UDPLITE " */
34		nf_log_buf_add(m, "PROTO=UDPLITE ");
35
36	if (fragment)
37		goto out;
38
39	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
40	uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
41	if (uh == NULL) {
42		nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
43
44		return 1;
45	}
46
47	/* Max length: 20 "SPT=65535 DPT=65535 " */
48	nf_log_buf_add(m, "SPT=%u DPT=%u LEN=%u ",
49		       ntohs(uh->source), ntohs(uh->dest), ntohs(uh->len));
50
51out:
52	return 0;
53}
54EXPORT_SYMBOL_GPL(nf_log_dump_udp_header);
55
56int nf_log_dump_tcp_header(struct nf_log_buf *m, const struct sk_buff *skb,
57			   u8 proto, int fragment, unsigned int offset,
58			   unsigned int logflags)
59{
60	struct tcphdr _tcph;
61	const struct tcphdr *th;
62
63	/* Max length: 10 "PROTO=TCP " */
64	nf_log_buf_add(m, "PROTO=TCP ");
65
66	if (fragment)
67		return 0;
68
69	/* Max length: 25 "INCOMPLETE [65535 bytes] " */
70	th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
71	if (th == NULL) {
72		nf_log_buf_add(m, "INCOMPLETE [%u bytes] ", skb->len - offset);
73		return 1;
74	}
75
76	/* Max length: 20 "SPT=65535 DPT=65535 " */
77	nf_log_buf_add(m, "SPT=%u DPT=%u ",
78		       ntohs(th->source), ntohs(th->dest));
79	/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
80	if (logflags & XT_LOG_TCPSEQ) {
81		nf_log_buf_add(m, "SEQ=%u ACK=%u ",
82			       ntohl(th->seq), ntohl(th->ack_seq));
83	}
84
85	/* Max length: 13 "WINDOW=65535 " */
86	nf_log_buf_add(m, "WINDOW=%u ", ntohs(th->window));
87	/* Max length: 9 "RES=0x3C " */
88	nf_log_buf_add(m, "RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) &
89					    TCP_RESERVED_BITS) >> 22));
90	/* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
91	if (th->cwr)
92		nf_log_buf_add(m, "CWR ");
93	if (th->ece)
94		nf_log_buf_add(m, "ECE ");
95	if (th->urg)
96		nf_log_buf_add(m, "URG ");
97	if (th->ack)
98		nf_log_buf_add(m, "ACK ");
99	if (th->psh)
100		nf_log_buf_add(m, "PSH ");
101	if (th->rst)
102		nf_log_buf_add(m, "RST ");
103	if (th->syn)
104		nf_log_buf_add(m, "SYN ");
105	if (th->fin)
106		nf_log_buf_add(m, "FIN ");
107	/* Max length: 11 "URGP=65535 " */
108	nf_log_buf_add(m, "URGP=%u ", ntohs(th->urg_ptr));
109
110	if ((logflags & XT_LOG_TCPOPT) && th->doff*4 > sizeof(struct tcphdr)) {
111		u_int8_t _opt[60 - sizeof(struct tcphdr)];
112		const u_int8_t *op;
113		unsigned int i;
114		unsigned int optsize = th->doff*4 - sizeof(struct tcphdr);
115
116		op = skb_header_pointer(skb, offset + sizeof(struct tcphdr),
117					optsize, _opt);
118		if (op == NULL) {
119			nf_log_buf_add(m, "OPT (TRUNCATED)");
120			return 1;
121		}
122
123		/* Max length: 127 "OPT (" 15*4*2chars ") " */
124		nf_log_buf_add(m, "OPT (");
125		for (i = 0; i < optsize; i++)
126			nf_log_buf_add(m, "%02X", op[i]);
127
128		nf_log_buf_add(m, ") ");
129	}
130
131	return 0;
132}
133EXPORT_SYMBOL_GPL(nf_log_dump_tcp_header);
134
135void nf_log_dump_sk_uid_gid(struct nf_log_buf *m, struct sock *sk)
136{
137	if (!sk || !sk_fullsock(sk))
138		return;
139
140	read_lock_bh(&sk->sk_callback_lock);
141	if (sk->sk_socket && sk->sk_socket->file) {
142		const struct cred *cred = sk->sk_socket->file->f_cred;
143		nf_log_buf_add(m, "UID=%u GID=%u ",
144			from_kuid_munged(&init_user_ns, cred->fsuid),
145			from_kgid_munged(&init_user_ns, cred->fsgid));
146	}
147	read_unlock_bh(&sk->sk_callback_lock);
148}
149EXPORT_SYMBOL_GPL(nf_log_dump_sk_uid_gid);
150
151void
152nf_log_dump_packet_common(struct nf_log_buf *m, u_int8_t pf,
153			  unsigned int hooknum, const struct sk_buff *skb,
154			  const struct net_device *in,
155			  const struct net_device *out,
156			  const struct nf_loginfo *loginfo, const char *prefix)
157{
158	nf_log_buf_add(m, KERN_SOH "%c%sIN=%s OUT=%s ",
159	       '0' + loginfo->u.log.level, prefix,
160	       in ? in->name : "",
161	       out ? out->name : "");
162#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
163	if (skb->nf_bridge) {
164		const struct net_device *physindev;
165		const struct net_device *physoutdev;
166
167		physindev = nf_bridge_get_physindev(skb);
168		if (physindev && in != physindev)
169			nf_log_buf_add(m, "PHYSIN=%s ", physindev->name);
170		physoutdev = nf_bridge_get_physoutdev(skb);
171		if (physoutdev && out != physoutdev)
172			nf_log_buf_add(m, "PHYSOUT=%s ", physoutdev->name);
173	}
174#endif
175}
176EXPORT_SYMBOL_GPL(nf_log_dump_packet_common);
177
178static int __init nf_log_common_init(void)
179{
180	return 0;
181}
182
183static void __exit nf_log_common_exit(void) {}
184
185module_init(nf_log_common_init);
186module_exit(nf_log_common_exit);
187
188MODULE_LICENSE("GPL");
189