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netfilter: nf_log_ipv4: rename to nf_log_syslog
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Netfilter has multiple log modules:
 nf_log_arp
 nf_log_bridge
 nf_log_ipv4
 nf_log_ipv6
 nf_log_netdev
 nfnetlink_log
 nf_log_common

With the exception of nfnetlink_log (packet is sent to userspace for
dissection/logging), all of them log to the kernel ringbuffer.

This is the first part of a series to merge all modules except
nfnetlink_log into a single module: nf_log_syslog.

This allows to reduce code.  After the series, only two log modules remain:
nfnetlink_log and nf_log_syslog. The latter provides the same
functionality as the old per-af log modules.

This renames nf_log_ipv4 to nf_log_syslog.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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@ummakynes
Florian Westphal authored and ummakynes committed Mar 30, 2021
1 parent cda1893 commit db3187a
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Showing 5 changed files with 76 additions and 65 deletions.
5 changes: 4 additions & 1 deletion net/ipv4/netfilter/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -81,7 +81,10 @@ config NF_LOG_ARP
config NF_LOG_IPV4
tristate "IPv4 packet logging"
default m if NETFILTER_ADVANCED=n
select NF_LOG_COMMON
select NF_LOG_SYSLOG
help
This is a backwards-compat option for the user's convenience
(e.g. when running oldconfig). It selects CONFIG_NF_LOG_SYSLOG.

config NF_REJECT_IPV4
tristate "IPv4 packet rejection"
Expand Down
1 change: 0 additions & 1 deletion net/ipv4/netfilter/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,6 @@ obj-$(CONFIG_NF_TPROXY_IPV4) += nf_tproxy_ipv4.o

# logging
obj-$(CONFIG_NF_LOG_ARP) += nf_log_arp.o
obj-$(CONFIG_NF_LOG_IPV4) += nf_log_ipv4.o

# reject
obj-$(CONFIG_NF_REJECT_IPV4) += nf_reject_ipv4.o
Expand Down
14 changes: 13 additions & 1 deletion net/netfilter/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,18 @@ config NF_LOG_NETDEV
tristate "Netdev packet logging"
select NF_LOG_COMMON

config NF_LOG_SYSLOG
tristate "Syslog packet logging"
default m if NETFILTER_ADVANCED=n
select NF_LOG_COMMON
help
This option enable support for packet logging via syslog.
It supports IPv4 and common transport protocols such as TCP and UDP.
This is a simpler but less flexible logging method compared to
CONFIG_NETFILTER_NETLINK_LOG.
If both are enabled the backend to use can be configured at run-time
by means of per-address-family sysctl tunables.

if NF_CONNTRACK
config NETFILTER_CONNCOUNT
tristate
Expand Down Expand Up @@ -923,7 +935,7 @@ config NETFILTER_XT_TARGET_LED
config NETFILTER_XT_TARGET_LOG
tristate "LOG target support"
select NF_LOG_COMMON
select NF_LOG_IPV4
select NF_LOG_SYSLOG
select NF_LOG_IPV6 if IP6_NF_IPTABLES
default m if NETFILTER_ADVANCED=n
help
Expand Down
1 change: 1 addition & 0 deletions net/netfilter/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,7 @@ nf_nat-y := nf_nat_core.o nf_nat_proto.o nf_nat_helper.o

# generic transport layer logging
obj-$(CONFIG_NF_LOG_COMMON) += nf_log_common.o
obj-$(CONFIG_NF_LOG_SYSLOG) += nf_log_syslog.o

# packet logging for netdev family
obj-$(CONFIG_NF_LOG_NETDEV) += nf_log_netdev.o
Expand Down
120 changes: 58 additions & 62 deletions net/ipv4/netfilter/nf_log_ipv4.c → net/netfilter/nf_log_syslog.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,28 +32,30 @@ static const struct nf_loginfo default_loginfo = {
};

/* One level of recursion won't kill us */
static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
const struct nf_loginfo *info,
const struct sk_buff *skb, unsigned int iphoff)
static noinline_for_stack void
dump_ipv4_packet(struct net *net, 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;
struct iphdr _iph;

if (info->type == NF_LOG_TYPE_LOG)
logflags = info->u.log.logflags;
else
logflags = NF_LOG_DEFAULT_MASK;

ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
if (ih == NULL) {
if (!ih) {
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 " */
* 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 " */
Expand All @@ -75,14 +77,14 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,

if ((logflags & NF_LOG_IPOPT) &&
ih->ihl * 4 > sizeof(struct iphdr)) {
const unsigned char *op;
unsigned char _opt[4 * 15 - sizeof(struct iphdr)];
const unsigned char *op;
unsigned int i, optsize;

optsize = ih->ihl * 4 - sizeof(struct iphdr);
op = skb_header_pointer(skb, iphoff+sizeof(_iph),
op = skb_header_pointer(skb, iphoff + sizeof(_iph),
optsize, _opt);
if (op == NULL) {
if (!op) {
nf_log_buf_add(m, "TRUNCATED");
return;
}
Expand All @@ -98,36 +100,31 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
case IPPROTO_TCP:
if (nf_log_dump_tcp_header(m, skb, ih->protocol,
ntohs(ih->frag_off) & IP_OFFSET,
iphoff+ih->ihl*4, logflags))
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))
iphoff + ih->ihl * 4))
return;
break;
case IPPROTO_ICMP: {
struct icmphdr _icmph;
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 };
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 };
struct icmphdr _icmph;

/* Max length: 11 "PROTO=ICMP " */
nf_log_buf_add(m, "PROTO=ICMP ");
Expand All @@ -138,9 +135,9 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
/* Max length: 25 "INCOMPLETE [65535 bytes] " */
ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
sizeof(_icmph), &_icmph);
if (ich == NULL) {
if (!ich) {
nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
skb->len - iphoff - ih->ihl*4);
skb->len - iphoff - ih->ihl * 4);
break;
}

Expand All @@ -150,9 +147,9 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
/* 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]) {
skb->len - iphoff - ih->ihl * 4 < required_len[ich->type]) {
nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
skb->len - iphoff - ih->ihl*4);
skb->len - iphoff - ih->ihl * 4);
break;
}

Expand Down Expand Up @@ -181,7 +178,7 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
if (!iphoff) { /* Only recurse once. */
nf_log_buf_add(m, "[");
dump_ipv4_packet(net, m, info, skb,
iphoff + ih->ihl*4+sizeof(_icmph));
iphoff + ih->ihl * 4 + sizeof(_icmph));
nf_log_buf_add(m, "] ");
}

Expand All @@ -196,8 +193,8 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
}
/* Max Length */
case IPPROTO_AH: {
struct ip_auth_hdr _ahdr;
const struct ip_auth_hdr *ah;
struct ip_auth_hdr _ahdr;

if (ntohs(ih->frag_off) & IP_OFFSET)
break;
Expand All @@ -206,11 +203,11 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
nf_log_buf_add(m, "PROTO=AH ");

/* Max length: 25 "INCOMPLETE [65535 bytes] " */
ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
ah = skb_header_pointer(skb, iphoff + ih->ihl * 4,
sizeof(_ahdr), &_ahdr);
if (ah == NULL) {
if (!ah) {
nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
skb->len - iphoff - ih->ihl*4);
skb->len - iphoff - ih->ihl * 4);
break;
}

Expand All @@ -219,8 +216,8 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
break;
}
case IPPROTO_ESP: {
struct ip_esp_hdr _esph;
const struct ip_esp_hdr *eh;
struct ip_esp_hdr _esph;

/* Max length: 10 "PROTO=ESP " */
nf_log_buf_add(m, "PROTO=ESP ");
Expand All @@ -229,11 +226,11 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
break;

/* Max length: 25 "INCOMPLETE [65535 bytes] " */
eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
eh = skb_header_pointer(skb, iphoff + ih->ihl * 4,
sizeof(_esph), &_esph);
if (eh == NULL) {
if (!eh) {
nf_log_buf_add(m, "INCOMPLETE [%u bytes] ",
skb->len - iphoff - ih->ihl*4);
skb->len - iphoff - ih->ihl * 4);
break;
}

Expand Down Expand Up @@ -270,8 +267,8 @@ static void dump_ipv4_packet(struct net *net, struct nf_log_buf *m,
}

static void dump_ipv4_mac_header(struct nf_log_buf *m,
const struct nf_loginfo *info,
const struct sk_buff *skb)
const struct nf_loginfo *info,
const struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
unsigned int logflags = 0;
Expand Down Expand Up @@ -329,7 +326,7 @@ static void nf_log_ip_packet(struct net *net, u_int8_t pf,
nf_log_dump_packet_common(m, pf, hooknum, skb, in,
out, loginfo, prefix);

if (in != NULL)
if (in)
dump_ipv4_mac_header(m, loginfo, skb);

dump_ipv4_packet(net, m, loginfo, skb, 0);
Expand All @@ -344,52 +341,51 @@ static struct nf_logger nf_ip_logger __read_mostly = {
.me = THIS_MODULE,
};

static int __net_init nf_log_ipv4_net_init(struct net *net)
static int __net_init nf_log_syslog_net_init(struct net *net)
{
return nf_log_set(net, NFPROTO_IPV4, &nf_ip_logger);
}

static void __net_exit nf_log_ipv4_net_exit(struct net *net)
static void __net_exit nf_log_syslog_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 struct pernet_operations nf_log_syslog_net_ops = {
.init = nf_log_syslog_net_init,
.exit = nf_log_syslog_net_exit,
};

static int __init nf_log_ipv4_init(void)
static int __init nf_log_syslog_init(void)
{
int ret;

ret = register_pernet_subsys(&nf_log_ipv4_net_ops);
ret = register_pernet_subsys(&nf_log_syslog_net_ops);
if (ret < 0)
return ret;

ret = nf_log_register(NFPROTO_IPV4, &nf_ip_logger);
if (ret < 0) {
pr_err("failed to register logger\n");
if (ret < 0)
goto err1;
}

return 0;

err1:
unregister_pernet_subsys(&nf_log_ipv4_net_ops);
unregister_pernet_subsys(&nf_log_syslog_net_ops);
return ret;
}

static void __exit nf_log_ipv4_exit(void)
static void __exit nf_log_syslog_exit(void)
{
unregister_pernet_subsys(&nf_log_ipv4_net_ops);
unregister_pernet_subsys(&nf_log_syslog_net_ops);
nf_log_unregister(&nf_ip_logger);
}

module_init(nf_log_ipv4_init);
module_exit(nf_log_ipv4_exit);
module_init(nf_log_syslog_init);
module_exit(nf_log_syslog_exit);

MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("Netfilter IPv4 packet logging");
MODULE_DESCRIPTION("Netfilter syslog packet logging");
MODULE_LICENSE("GPL");
MODULE_ALIAS("nf_log_ipv4");
MODULE_ALIAS_NF_LOGGER(AF_INET, 0);

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