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kernel-ark/net/ipv4/netfilter/nf_log_ipv4.c
Pablo Neira Ayuso fab4085f4e netfilter: log: nf_log_packet() as real unified interface 
Before this patch, the nf_loginfo parameter specified the logging
configuration in case the specified default logger was loaded. This
patch updates the semantics of the nf_loginfo parameter in
nf_log_packet() which now indicates the logger that you explicitly
want to use.

Thus, nf_log_packet() is exposed as an unified interface which
internally routes the log message to the corresponding logger type
by family.

The module dependencies are expressed by the new nf_logger_find_get()
and nf_logger_put() functions which bump the logger module refcount.
Thus, you can not remove logger modules that are used by rules anymore.

Another important effect of this change is that the family specific
module is only loaded when required. Therefore, xt_LOG and nft_log
will just trigger the autoload of the nf_log_{ip,ip6} modules
according to the family.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2014-06-27 13:20:13 +02:00

386 lines
9.9 KiB
C
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/* (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/if_arp.h>
#include <linux/ip.h>
#include <net/ipv6.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/tcp.h>
#include <net/route.h>
#include <linux/netfilter.h>
#include <linux/netfilter/xt_LOG.h>
#include <net/netfilter/nf_log.h>
static struct nf_loginfo default_loginfo = {
.type = NF_LOG_TYPE_LOG,
.u = {
.log = {
.level = 5,
.logflags = NF_LOG_MASK,
},
},
};
/* One level of recursion won't kill us */
static void dump_ipv4_packet(struct nf_log_buf *m,
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) {
nf_log_buf_add(m, "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 " */
nf_log_buf_add(m, "SRC=%pI4 DST=%pI4 ", &ih->saddr, &ih->daddr);
/* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
nf_log_buf_add(m, "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)
nf_log_buf_add(m, "CE ");
if (ntohs(ih->frag_off) & IP_DF)
nf_log_buf_add(m, "DF ");
if (ntohs(ih->frag_off) & IP_MF)
nf_log_buf_add(m, "MF ");
/* Max length: 11 "FRAG:65535 " */
if (ntohs(ih->frag_off) & IP_OFFSET)
nf_log_buf_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
if ((logflags & XT_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) {
nf_log_buf_add(m, "TRUNCATED");
return;
}
/* Max length: 127 "OPT (" 15*4*2chars ") " */
nf_log_buf_add(m, "OPT (");
for (i = 0; i < optsize; i++)
nf_log_buf_add(m, "%02X", op[i]);
nf_log_buf_add(m, ") ");
}
switch (ih->protocol) {
case IPPROTO_TCP:
if (nf_log_dump_tcp_header(m, skb, ih->protocol,
ntohs(ih->frag_off) & IP_OFFSET,
iphoff+ih->ihl*4, logflags))
return;
break;
case IPPROTO_UDP:
case IPPROTO_UDPLITE:
if (nf_log_dump_udp_header(m, skb, ih->protocol,
ntohs(ih->frag_off) & IP_OFFSET,
iphoff+ih->ihl*4))
return;
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 " */
nf_log_buf_add(m, "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) {
nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
skb->len - iphoff - ih->ihl*4);
break;
}
/* Max length: 18 "TYPE=255 CODE=255 " */
nf_log_buf_add(m, "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]) {
nf_log_buf_add(m, "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 " */
nf_log_buf_add(m, "ID=%u SEQ=%u ",
ntohs(ich->un.echo.id),
ntohs(ich->un.echo.sequence));
break;
case ICMP_PARAMETERPROB:
/* Max length: 14 "PARAMETER=255 " */
nf_log_buf_add(m, "PARAMETER=%u ",
ntohl(ich->un.gateway) >> 24);
break;
case ICMP_REDIRECT:
/* Max length: 24 "GATEWAY=255.255.255.255 " */
nf_log_buf_add(m, "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. */
nf_log_buf_add(m, "[");
dump_ipv4_packet(m, info, skb,
iphoff + ih->ihl*4+sizeof(_icmph));
nf_log_buf_add(m, "] ");
}
/* Max length: 10 "MTU=65535 " */
if (ich->type == ICMP_DEST_UNREACH &&
ich->code == ICMP_FRAG_NEEDED) {
nf_log_buf_add(m, "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 " */
nf_log_buf_add(m, "PROTO=AH ");
/* Max length: 25 "INCOMPLETE [65535 bytes] " */
ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
sizeof(_ahdr), &_ahdr);
if (ah == NULL) {
nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
skb->len - iphoff - ih->ihl*4);
break;
}
/* Length: 15 "SPI=0xF1234567 " */
nf_log_buf_add(m, "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 " */
nf_log_buf_add(m, "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) {
nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
skb->len - iphoff - ih->ihl*4);
break;
}
/* Length: 15 "SPI=0xF1234567 " */
nf_log_buf_add(m, "SPI=0x%x ", ntohl(eh->spi));
break;
}
/* Max length: 10 "PROTO 255 " */
default:
nf_log_buf_add(m, "PROTO=%u ", ih->protocol);
}
/* Max length: 15 "UID=4294967295 " */
if ((logflags & XT_LOG_UID) && !iphoff)
nf_log_dump_sk_uid_gid(m, skb->sk);
/* Max length: 16 "MARK=0xFFFFFFFF " */
if (!iphoff && skb->mark)
nf_log_buf_add(m, "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 void dump_ipv4_mac_header(struct nf_log_buf *m,
const struct nf_loginfo *info,
const struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
unsigned int logflags = 0;
if (info->type == NF_LOG_TYPE_LOG)
logflags = info->u.log.logflags;
if (!(logflags & XT_LOG_MACDECODE))
goto fallback;
switch (dev->type) {
case ARPHRD_ETHER:
nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
ntohs(eth_hdr(skb)->h_proto));
return;
default:
break;
}
fallback:
nf_log_buf_add(m, "MAC=");
if (dev->hard_header_len &&
skb->mac_header != skb->network_header) {
const unsigned char *p = skb_mac_header(skb);
unsigned int i;
nf_log_buf_add(m, "%02x", *p++);
for (i = 1; i < dev->hard_header_len; i++, p++)
nf_log_buf_add(m, ":%02x", *p);
}
nf_log_buf_add(m, " ");
}
static void nf_log_ip_packet(struct net *net, 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)
{
struct nf_log_buf *m;
/* FIXME: Disabled from containers until syslog ns is supported */
if (!net_eq(net, &init_net))
return;
m = nf_log_buf_open();
if (!loginfo)
loginfo = &default_loginfo;
nf_log_dump_packet_common(m, pf, hooknum, skb, in,
out, loginfo, prefix);
if (in != NULL)
dump_ipv4_mac_header(m, loginfo, skb);
dump_ipv4_packet(m, loginfo, skb, 0);
nf_log_buf_close(m);
}
static struct nf_logger nf_ip_logger __read_mostly = {
.name = "nf_log_ipv4",
.type = NF_LOG_TYPE_LOG,
.logfn = nf_log_ip_packet,
.me = THIS_MODULE,
};
static int __net_init nf_log_ipv4_net_init(struct net *net)
{
nf_log_set(net, NFPROTO_IPV4, &nf_ip_logger);
return 0;
}
static void __net_exit nf_log_ipv4_net_exit(struct net *net)
{
nf_log_unset(net, &nf_ip_logger);
}
static struct pernet_operations nf_log_ipv4_net_ops = {
.init = nf_log_ipv4_net_init,
.exit = nf_log_ipv4_net_exit,
};
static int __init nf_log_ipv4_init(void)
{
int ret;
ret = register_pernet_subsys(&nf_log_ipv4_net_ops);
if (ret < 0)
return ret;
nf_log_register(NFPROTO_IPV4, &nf_ip_logger);
return 0;
}
static void __exit nf_log_ipv4_exit(void)
{
unregister_pernet_subsys(&nf_log_ipv4_net_ops);
nf_log_unregister(&nf_ip_logger);
}
module_init(nf_log_ipv4_init);
module_exit(nf_log_ipv4_exit);
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("Netfilter IPv4 packet logging");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NF_LOGGER(AF_INET, 0);
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