From c68cd6cc21eb329c47ff020ff7412bf58176984e Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 17 Jun 2010 06:12:26 +0200 Subject: netfilter: nf_nat: support user-specified SNAT rules in LOCAL_IN 2.6.34 introduced 'conntrack zones' to deal with cases where packets from multiple identical networks are handled by conntrack/NAT. Packets are looped through veth devices, during which they are NATed to private addresses, after which they can continue normally through the stack and possibly have NAT rules applied a second time. This works well, but is needlessly complicated for cases where only a single SNAT/DNAT mapping needs to be applied to these packets. In that case, all that needs to be done is to assign each network to a seperate zone and perform NAT as usual. However this doesn't work for packets destined for the machine performing NAT itself since its corrently not possible to configure SNAT mappings for the LOCAL_IN chain. This patch adds a new INPUT chain to the NAT table and changes the targets performing SNAT to be usable in that chain. Example usage with two identical networks (192.168.0.0/24) on eth0/eth1: iptables -t raw -A PREROUTING -i eth0 -j CT --zone 1 iptables -t raw -A PREROUTING -i eth0 -j MARK --set-mark 1 iptables -t raw -A PREROUTING -i eth1 -j CT --zone 2 iptabels -t raw -A PREROUTING -i eth1 -j MARK --set-mark 2 iptables -t nat -A INPUT -m mark --mark 1 -j NETMAP --to 10.0.0.0/24 iptables -t nat -A POSTROUTING -m mark --mark 1 -j NETMAP --to 10.0.0.0/24 iptables -t nat -A INPUT -m mark --mark 2 -j NETMAP --to 10.0.1.0/24 iptables -t nat -A POSTROUTING -m mark --mark 2 -j NETMAP --to 10.0.1.0/24 iptables -t raw -A PREROUTING -d 10.0.0.0/24 -j CT --zone 1 iptables -t raw -A OUTPUT -d 10.0.0.0/24 -j CT --zone 1 iptables -t raw -A PREROUTING -d 10.0.1.0/24 -j CT --zone 2 iptables -t raw -A OUTPUT -d 10.0.1.0/24 -j CT --zone 2 iptables -t nat -A PREROUTING -d 10.0.0.0/24 -j NETMAP --to 192.168.0.0/24 iptables -t nat -A OUTPUT -d 10.0.0.0/24 -j NETMAP --to 192.168.0.0/24 iptables -t nat -A PREROUTING -d 10.0.1.0/24 -j NETMAP --to 192.168.0.0/24 iptables -t nat -A OUTPUT -d 10.0.1.0/24 -j NETMAP --to 192.168.0.0/24 Signed-off-by: Patrick McHardy --- net/ipv4/netfilter/ipt_NETMAP.c | 6 ++++-- net/ipv4/netfilter/nf_nat_rule.c | 10 ++++++---- net/ipv4/netfilter/nf_nat_standalone.c | 8 +------- 3 files changed, 11 insertions(+), 13 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/ipt_NETMAP.c b/net/ipv4/netfilter/ipt_NETMAP.c index f43867d..6cdb298 100644 --- a/net/ipv4/netfilter/ipt_NETMAP.c +++ b/net/ipv4/netfilter/ipt_NETMAP.c @@ -48,7 +48,8 @@ netmap_tg(struct sk_buff *skb, const struct xt_action_param *par) NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING || par->hooknum == NF_INET_POST_ROUTING || - par->hooknum == NF_INET_LOCAL_OUT); + par->hooknum == NF_INET_LOCAL_OUT || + par->hooknum == NF_INET_LOCAL_IN); ct = nf_ct_get(skb, &ctinfo); netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip); @@ -77,7 +78,8 @@ static struct xt_target netmap_tg_reg __read_mostly = { .table = "nat", .hooks = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_POST_ROUTING) | - (1 << NF_INET_LOCAL_OUT), + (1 << NF_INET_LOCAL_OUT) | + (1 << NF_INET_LOCAL_IN), .checkentry = netmap_tg_check, .me = THIS_MODULE }; diff --git a/net/ipv4/netfilter/nf_nat_rule.c b/net/ipv4/netfilter/nf_nat_rule.c index 98ed782..ebbd319 100644 --- a/net/ipv4/netfilter/nf_nat_rule.c +++ b/net/ipv4/netfilter/nf_nat_rule.c @@ -28,7 +28,8 @@ #define NAT_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \ (1 << NF_INET_POST_ROUTING) | \ - (1 << NF_INET_LOCAL_OUT)) + (1 << NF_INET_LOCAL_OUT) | \ + (1 << NF_INET_LOCAL_IN)) static const struct xt_table nat_table = { .name = "nat", @@ -45,7 +46,8 @@ ipt_snat_target(struct sk_buff *skb, const struct xt_action_param *par) enum ip_conntrack_info ctinfo; const struct nf_nat_multi_range_compat *mr = par->targinfo; - NF_CT_ASSERT(par->hooknum == NF_INET_POST_ROUTING); + NF_CT_ASSERT(par->hooknum == NF_INET_POST_ROUTING || + par->hooknum == NF_INET_LOCAL_IN); ct = nf_ct_get(skb, &ctinfo); @@ -99,7 +101,7 @@ static int ipt_dnat_checkentry(const struct xt_tgchk_param *par) return 0; } -unsigned int +static unsigned int alloc_null_binding(struct nf_conn *ct, unsigned int hooknum) { /* Force range to this IP; let proto decide mapping for @@ -141,7 +143,7 @@ static struct xt_target ipt_snat_reg __read_mostly = { .target = ipt_snat_target, .targetsize = sizeof(struct nf_nat_multi_range_compat), .table = "nat", - .hooks = 1 << NF_INET_POST_ROUTING, + .hooks = (1 << NF_INET_POST_ROUTING) | (1 << NF_INET_LOCAL_IN), .checkentry = ipt_snat_checkentry, .family = AF_INET, }; diff --git a/net/ipv4/netfilter/nf_nat_standalone.c b/net/ipv4/netfilter/nf_nat_standalone.c index 6723c68..95481fe 100644 --- a/net/ipv4/netfilter/nf_nat_standalone.c +++ b/net/ipv4/netfilter/nf_nat_standalone.c @@ -131,13 +131,7 @@ nf_nat_fn(unsigned int hooknum, if (!nf_nat_initialized(ct, maniptype)) { unsigned int ret; - if (hooknum == NF_INET_LOCAL_IN) - /* LOCAL_IN hook doesn't have a chain! */ - ret = alloc_null_binding(ct, hooknum); - else - ret = nf_nat_rule_find(skb, hooknum, in, out, - ct); - + ret = nf_nat_rule_find(skb, hooknum, in, out, ct); if (ret != NF_ACCEPT) return ret; } else -- cgit v1.1 From cf377eb4aeded926375d4d0fe0b66ba95f0521e1 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 28 Jun 2010 14:12:41 +0200 Subject: netfilter: ipt_LOG/ip6t_LOG: remove comparison within loop Remove the comparison within the loop to print the macheader by prepending the colon to all but the first printk. Based on suggestion by Jan Engelhardt . Signed-off-by: Patrick McHardy --- net/ipv4/netfilter/ipt_LOG.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/ipt_LOG.c b/net/ipv4/netfilter/ipt_LOG.c index 5234f4f..0a452a5 100644 --- a/net/ipv4/netfilter/ipt_LOG.c +++ b/net/ipv4/netfilter/ipt_LOG.c @@ -411,12 +411,12 @@ ipt_log_packet(u_int8_t pf, 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(" "); + + printk("%02x", *p++); + for (i = 1; i < skb->dev->hard_header_len; i++, p++) + printk(":%02x", *p); + } + printk(" "); } dump_packet(loginfo, skb, 0); -- cgit v1.1 From 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 28 Jun 2010 14:16:08 +0200 Subject: netfilter: ipt_LOG/ip6t_LOG: add option to print decoded MAC header The LOG targets print the entire MAC header as one long string, which is not readable very well: IN=eth0 OUT= MAC=00:15:f2:24:91:f8:00:1b:24:dc:61:e6:08:00 ... Add an option to decode known header formats (currently just ARPHRD_ETHER devices) in their individual fields: IN=eth0 OUT= MACSRC=00:1b:24:dc:61:e6 MACDST=00:15:f2:24:91:f8 MACPROTO=0800 ... IN=eth0 OUT= MACSRC=00:1b:24:dc:61:e6 MACDST=00:15:f2:24:91:f8 MACPROTO=86dd ... The option needs to be explicitly enabled by userspace to avoid breaking existing parsers. Signed-off-by: Patrick McHardy --- net/ipv4/netfilter/ipt_LOG.c | 54 ++++++++++++++++++++++++++++++++------------ 1 file changed, 40 insertions(+), 14 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/ipt_LOG.c b/net/ipv4/netfilter/ipt_LOG.c index 0a452a5..915fc17 100644 --- a/net/ipv4/netfilter/ipt_LOG.c +++ b/net/ipv4/netfilter/ipt_LOG.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -363,6 +364,42 @@ static void dump_packet(const struct nf_loginfo *info, /* maxlen = 230+ 91 + 230 + 252 = 803 */ } +static void dump_mac_header(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 & IPT_LOG_MACDECODE)) + goto fallback; + + switch (dev->type) { + case ARPHRD_ETHER: + printk("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: + printk("MAC="); + if (dev->hard_header_len && + skb->mac_header != skb->network_header) { + const unsigned char *p = skb_mac_header(skb); + unsigned int i; + + printk("%02x", *p++); + for (i = 1; i < dev->hard_header_len; i++, p++) + printk(":%02x", *p); + } + printk(" "); +} + static struct nf_loginfo default_loginfo = { .type = NF_LOG_TYPE_LOG, .u = { @@ -404,20 +441,9 @@ ipt_log_packet(u_int8_t pf, } #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); - - printk("%02x", *p++); - for (i = 1; i < skb->dev->hard_header_len; i++, p++) - printk(":%02x", *p); - } - printk(" "); - } + /* MAC logging for input path only. */ + if (in && !out) + dump_mac_header(loginfo, skb); dump_packet(loginfo, skb, 0); printk("\n"); -- cgit v1.1