[NETFILTER]: ipt_REJECT: remove largely duplicate route_reverse function (9d02002d) · Commits · 戴 / test

net/ipv4/netfilter/ipt_REJECT.c

+19 −78

Original line number	Diff line number	Diff line
		@@ -38,76 +38,16 @@ MODULE_DESCRIPTION("iptables REJECT target module");
		#define DEBUGP(format, args...)
		#endif

		static inline struct rtable route_reverse(struct sk_buff skb,
		struct tcphdr *tcph, int hook)
		{
		struct iphdr *iph = skb->nh.iph;
		struct dst_entry *odst;
		struct flowi fl = {};
		struct rtable *rt;

		/* We don't require ip forwarding to be enabled to be able to
		* send a RST reply for bridged traffic. */
		if (hook != NF_IP_FORWARD
		#ifdef CONFIG_BRIDGE_NETFILTER
		\|\| (skb->nf_bridge && skb->nf_bridge->mask & BRNF_BRIDGED)
		#endif
		) {
		fl.nl_u.ip4_u.daddr = iph->saddr;
		if (hook == NF_IP_LOCAL_IN)
		fl.nl_u.ip4_u.saddr = iph->daddr;
		fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);

		if (ip_route_output_key(&rt, &fl) != 0)
		return NULL;
		} else {
		/* non-local src, find valid iif to satisfy
		* rp-filter when calling ip_route_input. */
		fl.nl_u.ip4_u.daddr = iph->daddr;
		if (ip_route_output_key(&rt, &fl) != 0)
		return NULL;

		odst = skb->dst;
		if (ip_route_input(skb, iph->saddr, iph->daddr,
		RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
		dst_release(&rt->u.dst);
		return NULL;
		}
		dst_release(&rt->u.dst);
		rt = (struct rtable *)skb->dst;
		skb->dst = odst;

		fl.nl_u.ip4_u.daddr = iph->saddr;
		fl.nl_u.ip4_u.saddr = iph->daddr;
		fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
		}

		if (rt->u.dst.error) {
		dst_release(&rt->u.dst);
		return NULL;
		}

		fl.proto = IPPROTO_TCP;
		fl.fl_ip_sport = tcph->dest;
		fl.fl_ip_dport = tcph->source;
		security_skb_classify_flow(skb, &fl);

		xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0);

		return rt;
		}

		/* Send RST reply */
		static void send_reset(struct sk_buff *oldskb, int hook)
		{
		struct sk_buff *nskb;
		struct iphdr *iph = oldskb->nh.iph;
		struct tcphdr _otcph, oth, tcph;
		struct rtable *rt;
		__be16 tmp_port;
		__be32 tmp_addr;
		int needs_ack;
		int hh_len;
		unsigned int addr_type;

		/* IP header checks: fragment. */
		if (oldskb->nh.iph->frag_off & htons(IP_OFFSET))
		@@ -126,23 +66,13 @@ static void send_reset(struct sk_buff *oldskb, int hook)
		if (nf_ip_checksum(oldskb, hook, iph->ihl * 4, IPPROTO_TCP))
		return;

		if ((rt = route_reverse(oldskb, oth, hook)) == NULL)
		return;

		hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);

		/* We need a linear, writeable skb. We also need to expand
		headroom in case hh_len of incoming interface < hh_len of
		outgoing interface */
		nskb = skb_copy_expand(oldskb, hh_len, skb_tailroom(oldskb),
		nskb = skb_copy_expand(oldskb, LL_MAX_HEADER, skb_tailroom(oldskb),
		GFP_ATOMIC);
		if (!nskb) {
		dst_release(&rt->u.dst);
		if (!nskb)
		return;
		}

		dst_release(nskb->dst);
		nskb->dst = &rt->u.dst;

		/* This packet will not be the same as the other: clear nf fields */
		nf_reset(nskb);
		@@ -184,6 +114,21 @@ static void send_reset(struct sk_buff *oldskb, int hook)
		tcph->window = 0;
		tcph->urg_ptr = 0;

		/* Set DF, id = 0 */
		nskb->nh.iph->frag_off = htons(IP_DF);
		nskb->nh.iph->id = 0;

		addr_type = RTN_UNSPEC;
		if (hook != NF_IP_FORWARD
		#ifdef CONFIG_BRIDGE_NETFILTER
		\|\| (nskb->nf_bridge && nskb->nf_bridge->mask & BRNF_BRIDGED)
		#endif
		)
		addr_type = RTN_LOCAL;

		if (ip_route_me_harder(&nskb, addr_type))
		goto free_nskb;

		/* Adjust TCP checksum */
		nskb->ip_summed = CHECKSUM_NONE;
		tcph->check = 0;
		@@ -192,12 +137,8 @@ static void send_reset(struct sk_buff *oldskb, int hook)
		nskb->nh.iph->daddr,
		csum_partial((char *)tcph,
		sizeof(struct tcphdr), 0));

		/* Adjust IP TTL, DF */
		/* Adjust IP TTL */
		nskb->nh.iph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
		/* Set DF, id = 0 */
		nskb->nh.iph->frag_off = htons(IP_DF);
		nskb->nh.iph->id = 0;

		/* Adjust IP checksum */
		nskb->nh.iph->check = 0;

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