cregit-Linux how code gets into the kernel

Release 4.8 net/ipv4/netfilter.c

Directory: net/ipv4
/*
 * IPv4 specific functions of netfilter core
 *
 * Rusty Russell (C) 2000 -- This code is GPL.
 * Patrick McHardy (C) 2006-2012
 */
#include <linux/kernel.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/ip.h>
#include <linux/skbuff.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <net/route.h>
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/netfilter/nf_queue.h>

/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */



int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_type)
{
	const struct iphdr *iph = ip_hdr(skb);
	struct rtable *rt;
	struct flowi4 fl4 = {};
	__be32 saddr = iph->saddr;
	__u8 flags = skb->sk ? inet_sk_flowi_flags(skb->sk) : 0;
	unsigned int hh_len;

	if (addr_type == RTN_UNSPEC)
		addr_type = inet_addr_type(net, saddr);
	if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST)
		flags |= FLOWI_FLAG_ANYSRC;
	else
		saddr = 0;

	/* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
         * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook.
         */
	fl4.daddr = iph->daddr;
	fl4.saddr = saddr;
	fl4.flowi4_tos = RT_TOS(iph->tos);
	fl4.flowi4_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0;
	fl4.flowi4_mark = skb->mark;
	fl4.flowi4_flags = flags;
	rt = ip_route_output_key(net, &fl4);
	if (IS_ERR(rt))
		return PTR_ERR(rt);

	/* Drop old route. */
	skb_dst_drop(skb);
	skb_dst_set(skb, &rt->dst);

	if (skb_dst(skb)->error)
		return skb_dst(skb)->error;

#ifdef CONFIG_XFRM
	if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
	    xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) {
		struct dst_entry *dst = skb_dst(skb);
		skb_dst_set(skb, NULL);
		dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), skb->sk, 0);
		if (IS_ERR(dst))
			return PTR_ERR(dst);
		skb_dst_set(skb, dst);
	}
#endif

	/* Change in oif may mean change in hh_len. */
	hh_len = skb_dst(skb)->dev->hard_header_len;
	if (skb_headroom(skb) < hh_len &&
	    pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
				0, GFP_ATOMIC))
		return -ENOMEM;

	return 0;
}

Contributors
PersonTokensPropCommitsCommitProp
harald welteharald welte11331.83%14.55%


patrick mchardypatrick mchardy6016.90%313.64%


julian anastasovjulian anastasov4312.11%29.09%


david s. millerdavid s. miller4111.55%313.64%


eric dumazeteric dumazet3810.70%29.09%


herbert xuherbert xu267.32%29.09%


simon hormansimon horman133.66%14.55%


eric w. biedermaneric w. biederman51.41%14.55%


arnaldo carvalho de meloarnaldo carvalho de melo41.13%14.55%


kovacs krisztiankovacs krisztian30.85%14.55%


alexey dobriyanalexey dobriyan30.85%29.09%


paul guopaul guo30.85%14.55%


denis v. lunevdenis v. lunev20.56%14.55%


thomas grafthomas graf10.28%14.55%


Total355100.00%22100.00%




EXPORT_SYMBOL(ip_route_me_harder);

/*
 * Extra routing may needed on local out, as the QUEUE target never
 * returns control to the table.
 */


struct ip_rt_info {
	
__be32 daddr;
	
__be32 saddr;
	
u_int8_t tos;
	
u_int32_t mark;
};




static void nf_ip_saveroute(const struct sk_buff *skb,
			    struct nf_queue_entry *entry)
{
	struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);

	if (entry->state.hook == NF_INET_LOCAL_OUT) {
		const struct iphdr *iph = ip_hdr(skb);

		rt_info->tos = iph->tos;
		rt_info->daddr = iph->daddr;
		rt_info->saddr = iph->saddr;
		rt_info->mark = skb->mark;
	}
}


Contributors
PersonTokensPropCommitsCommitProp
harald welteharald welte6275.61%114.29%


eric leblonderic leblond89.76%114.29%


patrick mchardypatrick mchardy78.54%342.86%


arnaldo carvalho de meloarnaldo carvalho de melo33.66%114.29%


david s. millerdavid s. miller22.44%114.29%


Total82100.00%7100.00%






static int nf_ip_reroute(struct net *net, struct sk_buff *skb,
			 const struct nf_queue_entry *entry)
{
	const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);

	if (entry->state.hook == NF_INET_LOCAL_OUT) {
		const struct iphdr *iph = ip_hdr(skb);

		if (!(iph->tos == rt_info->tos &&
		      skb->mark == rt_info->mark &&
		      iph->daddr == rt_info->daddr &&
		      iph->saddr == rt_info->saddr))
			return ip_route_me_harder(net, skb, RTN_UNSPEC);
	}
	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
harald welteharald welte7368.87%19.09%


eric leblonderic leblond87.55%19.09%


patrick mchardypatrick mchardy76.60%327.27%


eric w. biedermaneric w. biederman76.60%218.18%


arnaldo carvalho de meloarnaldo carvalho de melo43.77%19.09%


herbert xuherbert xu32.83%19.09%


simon hormansimon horman21.89%19.09%


david s. millerdavid s. miller21.89%19.09%


Total106100.00%11100.00%






__sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
			    unsigned int dataoff, u_int8_t protocol)
{
	const struct iphdr *iph = ip_hdr(skb);
	__sum16 csum = 0;

	switch (skb->ip_summed) {
	case CHECKSUM_COMPLETE:
		if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
			break;
		if ((protocol == 0 && !csum_fold(skb->csum)) ||
		    !csum_tcpudp_magic(iph->saddr, iph->daddr,
				       skb->len - dataoff, protocol,
				       skb->csum)) {
			skb->ip_summed = CHECKSUM_UNNECESSARY;
			break;
		}
		/* fall through */
	case CHECKSUM_NONE:
		if (protocol == 0)
			skb->csum = 0;
		else
			skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
						       skb->len - dataoff,
						       protocol, 0);
		csum = __skb_checksum_complete(skb);
	}
	return csum;
}

Contributors
PersonTokensPropCommitsCommitProp
patrick mchardypatrick mchardy15496.25%360.00%


arnaldo carvalho de meloarnaldo carvalho de melo42.50%120.00%


al viroal viro21.25%120.00%


Total160100.00%5100.00%




EXPORT_SYMBOL(nf_ip_checksum);




static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
				      unsigned int dataoff, unsigned int len,
				      u_int8_t protocol)
{
	const struct iphdr *iph = ip_hdr(skb);
	__sum16 csum = 0;

	switch (skb->ip_summed) {
	case CHECKSUM_COMPLETE:
		if (len == skb->len - dataoff)
			return nf_ip_checksum(skb, hook, dataoff, protocol);
		/* fall through */
	case CHECKSUM_NONE:
		skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, protocol,
					       skb->len - dataoff, 0);
		skb->ip_summed = CHECKSUM_NONE;
		return __skb_checksum_complete_head(skb, dataoff + len);
	}
	return csum;
}


Contributors
PersonTokensPropCommitsCommitProp
patrick mchardypatrick mchardy12198.37%150.00%


shan weishan wei21.63%150.00%


Total123100.00%2100.00%






static int nf_ip_route(struct net *net, struct dst_entry **dst,
		       struct flowi *fl, bool strict __always_unused)
{
	struct rtable *rt = ip_route_output_key(net, &fl->u.ip4);
	if (IS_ERR(rt))
		return PTR_ERR(rt);
	*dst = &rt->dst;
	return 0;
}


Contributors
PersonTokensPropCommitsCommitProp
david s. millerdavid s. miller3450.75%233.33%


patrick mchardypatrick mchardy2232.84%116.67%


florian westphalflorian westphal1014.93%233.33%


denis v. lunevdenis v. lunev11.49%116.67%


Total67100.00%6100.00%




static const struct nf_afinfo nf_ip_afinfo = {
	.family			= AF_INET,
	.checksum		= nf_ip_checksum,
	.checksum_partial	= nf_ip_checksum_partial,
	.route			= nf_ip_route,
	.saveroute		= nf_ip_saveroute,
	.reroute		= nf_ip_reroute,
	.route_key_size		= sizeof(struct ip_rt_info),
};




static int __init ipv4_netfilter_init(void)
{
	return nf_register_afinfo(&nf_ip_afinfo);
}

Contributors
PersonTokensPropCommitsCommitProp
harald welteharald welte1275.00%125.00%


patrick mchardypatrick mchardy212.50%125.00%


jan beulichjan beulich16.25%125.00%


andrew mortonandrew morton16.25%125.00%


Total16100.00%4100.00%




subsys_initcall(ipv4_netfilter_init);

Overall Contributors
PersonTokensPropCommitsCommitProp
patrick mchardypatrick mchardy42141.11%1328.26%


harald welteharald welte31130.37%24.35%


david s. millerdavid s. miller797.71%48.70%


julian anastasovjulian anastasov434.20%24.35%


eric dumazeteric dumazet383.71%24.35%


herbert xuherbert xu323.12%24.35%


eric leblonderic leblond191.86%12.17%


arnaldo carvalho de meloarnaldo carvalho de melo151.46%12.17%


simon hormansimon horman151.46%12.17%


eric w. biedermaneric w. biederman121.17%24.35%


florian westphalflorian westphal100.98%24.35%


al viroal viro40.39%24.35%


paul gortmakerpaul gortmaker40.39%24.35%


kovacs krisztiankovacs krisztian30.29%12.17%


alexey dobriyanalexey dobriyan30.29%24.35%


paul guopaul guo30.29%12.17%


denis v. lunevdenis v. lunev30.29%12.17%


tejun heotejun heo30.29%12.17%


shan weishan wei20.20%12.17%


andrew mortonandrew morton20.20%12.17%


jan beulichjan beulich10.10%12.17%


thomas grafthomas graf10.10%12.17%


Total1024100.00%46100.00%

  
Directory: net/ipv4



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