42 static bool ip_may_fragment(const struct sk_buff *skb)  in ip_may_fragment()  argument
44 	return unlikely((ip_hdr(skb)->frag_off & htons(IP_DF)) == 0) ||  in ip_may_fragment()
45 		skb->ignore_df;  in ip_may_fragment()
48 static bool ip_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)  in ip_exceeds_mtu()  argument
50 	if (skb->len <= mtu)  in ip_exceeds_mtu()
53 	if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu)  in ip_exceeds_mtu()
60 static int ip_forward_finish(struct sock *sk, struct sk_buff *skb)  in ip_forward_finish()  argument
62 	struct ip_options *opt	= &(IPCB(skb)->opt);  in ip_forward_finish()
64 	IP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_OUTFORWDATAGRAMS);  in ip_forward_finish()
65 	IP_ADD_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_OUTOCTETS, skb->len);  in ip_forward_finish()
68 		ip_forward_options(skb);  in ip_forward_finish()
70 	skb_sender_cpu_clear(skb);  in ip_forward_finish()
71 	return dst_output_sk(sk, skb);  in ip_forward_finish()
74 int ip_forward(struct sk_buff *skb)  in ip_forward()  argument
79 	struct ip_options *opt	= &(IPCB(skb)->opt);  in ip_forward()
82 	if (skb->pkt_type != PACKET_HOST)  in ip_forward()
85 	if (unlikely(skb->sk))  in ip_forward()
88 	if (skb_warn_if_lro(skb))  in ip_forward()
91 	if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb))  in ip_forward()
94 	if (IPCB(skb)->opt.router_alert && ip_call_ra_chain(skb))  in ip_forward()
97 	skb_forward_csum(skb);  in ip_forward()
104 	if (ip_hdr(skb)->ttl <= 1)  in ip_forward()
107 	if (!xfrm4_route_forward(skb))  in ip_forward()
110 	rt = skb_rtable(skb);  in ip_forward()
115 	IPCB(skb)->flags |= IPSKB_FORWARDED;  in ip_forward()
117 	if (!ip_may_fragment(skb) && ip_exceeds_mtu(skb, mtu)) {  in ip_forward()
119 		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,  in ip_forward()
125 	if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+rt->dst.header_len))  in ip_forward()
127 	iph = ip_hdr(skb);  in ip_forward()
136 	if (IPCB(skb)->flags & IPSKB_DOREDIRECT && !opt->srr &&  in ip_forward()
137 	    !skb_sec_path(skb))  in ip_forward()
138 		ip_rt_send_redirect(skb);  in ip_forward()
140 	skb->priority = rt_tos2priority(iph->tos);  in ip_forward()
142 	return NF_HOOK(NFPROTO_IPV4, NF_INET_FORWARD, NULL, skb,  in ip_forward()
143 		       skb->dev, rt->dst.dev, ip_forward_finish);  in ip_forward()
149 	 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_SR_FAILED, 0);  in ip_forward()
154 	IP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_INHDRERRORS);  in ip_forward()
155 	icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0);  in ip_forward()
157 	kfree_skb(skb);  in ip_forward()