// SPDX-License-Identifier: GPL-2.0-or-later/* * IPv6 specific functions of netfilter core * * Rusty Russell (C) 2000 * Patrick McHardy (C) 2006-2012 */#include <linux/kernel.h>#include <linux/init.h>#include <linux/ipv6.h>#include <linux/netfilter.h>#include <linux/netfilter_ipv6.h>#include <linux/export.h>#include <net/addrconf.h>#include <net/dst.h>#include <net/ipv6.h>#include <net/ip6_route.h>#include <net/xfrm.h>#include <net/netfilter/nf_queue.h>#include <net/netfilter/nf_conntrack_bridge.h>#include <net/netfilter/ipv6/nf_defrag_ipv6.h>#include "../bridge/br_private.h" int ip6_route_me_harder(struct net *net, struct sock *sk_partial, struct sk_buff *skb){	const struct ipv6hdr *iph = ipv6_hdr(skb);	struct sock *sk = sk_to_full_sk(sk_partial);	struct net_device *dev = skb_dst_dev(skb);	struct flow_keys flkeys;	unsigned int hh_len;	struct dst_entry *dst;	int strict = (ipv6_addr_type(&iph->daddr) &		      (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));	struct flowi6 fl6 = {		.flowi6_l3mdev = l3mdev_master_ifindex(dev),		.flowi6_mark = skb->mark,		.flowi6_uid = sock_net_uid(net, sk),		.daddr = iph->daddr,		.saddr = iph->saddr,		.flowlabel = ip6_flowinfo(iph),	};	int err; 	if (sk && sk->sk_bound_dev_if)		fl6.flowi6_oif = sk->sk_bound_dev_if;	else if (strict)		fl6.flowi6_oif = dev->ifindex; 	fib6_rules_early_flow_dissect(net, skb, &fl6, &flkeys);	dst = ip6_route_output(net, sk, &fl6);	err = dst->error;	if (err) {		IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);		net_dbg_ratelimited("ip6_route_me_harder: No more route\n");		dst_release(dst);		return err;	} 	/* Drop old route. */	skb_dst_drop(skb); 	skb_dst_set(skb, dst); #ifdef CONFIG_XFRM	if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&	    xfrm_decode_session(net, skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {		/* ignore return value from skb_dstref_steal, xfrm_lookup takes		 * care of dropping the refcnt if needed.		 */		skb_dstref_steal(skb);		dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), 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_dev(skb)->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;}EXPORT_SYMBOL(ip6_route_me_harder); int __nf_ip6_route(struct net *net, struct dst_entry **dst,		   struct flowi *fl, bool strict){	static const struct ipv6_pinfo fake_pinfo;	static const struct inet_sock fake_sk = {		/* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */		.sk.sk_bound_dev_if = 1,		.pinet6 = (struct ipv6_pinfo *) &fake_pinfo,	};	const void *sk = strict ? &fake_sk : NULL;	struct dst_entry *result;	int err; 	result = ip6_route_output(net, sk, &fl->u.ip6);	err = result->error;	if (err)		dst_release(result);	else		*dst = result;	return err;}EXPORT_SYMBOL_GPL(__nf_ip6_route); int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,		    struct nf_bridge_frag_data *data,		    int (*output)(struct net *, struct sock *sk,				  const struct nf_bridge_frag_data *data,				  struct sk_buff *)){	int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;	u8 tstamp_type = skb->tstamp_type;	ktime_t tstamp = skb->tstamp;	struct ip6_frag_state state;	u8 *prevhdr, nexthdr = 0;	unsigned int mtu, hlen, nexthdr_offset;	int hroom, err = 0;	__be32 frag_id; 	err = ip6_find_1stfragopt(skb, &prevhdr);	if (err < 0)		goto blackhole;	hlen = err;	nexthdr = *prevhdr;	nexthdr_offset = prevhdr - skb_network_header(skb); 	mtu = skb->dev->mtu;	if (frag_max_size > mtu ||	    frag_max_size < IPV6_MIN_MTU)		goto blackhole; 	mtu = frag_max_size;	if (mtu < hlen + sizeof(struct frag_hdr) + 8)		goto blackhole;	mtu -= hlen + sizeof(struct frag_hdr); 	frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr,				    &ipv6_hdr(skb)->saddr); 	if (skb->ip_summed == CHECKSUM_PARTIAL &&	    (err = skb_checksum_help(skb)))		goto blackhole; 	prevhdr = skb_network_header(skb) + nexthdr_offset;	hroom = LL_RESERVED_SPACE(skb->dev);	if (skb_has_frag_list(skb)) {		unsigned int first_len = skb_pagelen(skb);		struct ip6_fraglist_iter iter;		struct sk_buff *frag2; 		if (first_len - hlen > mtu)			goto blackhole; 		if (skb_cloned(skb) ||		    skb_headroom(skb) < (hroom + sizeof(struct frag_hdr)))			goto slow_path; 		skb_walk_frags(skb, frag2) {			if (frag2->len > mtu)				goto blackhole; 			/* Partially cloned skb? */			if (skb_shared(frag2) ||			    skb_headroom(frag2) < (hlen + hroom + sizeof(struct frag_hdr)))				goto slow_path;		} 		err = ip6_fraglist_init(skb, hlen, prevhdr, nexthdr, frag_id,					&iter);		if (err < 0)			goto blackhole; 		for (;;) {			/* Prepare header of the next frame,			 * before previous one went down.			 */			if (iter.frag)				ip6_fraglist_prepare(skb, &iter); 			skb_set_delivery_time(skb, tstamp, tstamp_type);			err = output(net, sk, data, skb);			if (err || !iter.frag)				break; 			skb = ip6_fraglist_next(&iter);		} 		kfree(iter.tmp_hdr);		if (!err)			return 0; 		kfree_skb_list(iter.frag);		return err;	}slow_path:	/* This is a linearized skbuff, the original geometry is lost for us.	 * This may also be a clone skbuff, we could preserve the geometry for	 * the copies but probably not worth the effort.	 */	ip6_frag_init(skb, hlen, mtu, skb->dev->needed_tailroom,		      LL_RESERVED_SPACE(skb->dev), prevhdr, nexthdr, frag_id,		      &state); 	while (state.left > 0) {		struct sk_buff *skb2; 		skb2 = ip6_frag_next(skb, &state);		if (IS_ERR(skb2)) {			err = PTR_ERR(skb2);			goto blackhole;		} 		skb_set_delivery_time(skb2, tstamp, tstamp_type);		err = output(net, sk, data, skb2);		if (err)			goto blackhole;	}	consume_skb(skb);	return err; blackhole:	kfree_skb(skb);	return 0;}EXPORT_SYMBOL_GPL(br_ip6_fragment);