net/ipv6/ip6_output.c

144 				    struct sk_buff *skb, unsigned int mtu)
171 		err = segs->len > mtu ?
182 				 struct sk_buff *skb, unsigned int mtu)
185 	    !skb_gso_validate_network_len(skb, mtu))
186 		return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu);
193 	unsigned int mtu;
203 	mtu = ip6_skb_dst_mtu(skb);
205 		return ip6_finish_output_gso(net, sk, skb, mtu);
207 	if (skb->len > mtu ||
279 	u32 mtu;
344 	mtu = dst_mtu(dst);
345 	if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
367 	ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
475 static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
477 	if (skb->len <= mtu)
481 	if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu)
487 	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
501 	u32 mtu;
633 	mtu = ip6_dst_mtu_maybe_forward(dst, true);
634 	if (mtu < IPV6_MIN_MTU)
635 		mtu = IPV6_MIN_MTU;
637 	if (ip6_pkt_too_big(skb, mtu)) {
640 		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
758 void ip6_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int mtu,
767 	state->mtu = mtu;
787 	/* IF: it doesn't fit, use 'mtu' - the data space left */
788 	if (len > state->mtu)
789 		len = state->mtu;
864 	unsigned int mtu, hlen, nexthdr_offset;
877 	mtu = ip6_skb_dst_mtu(skb);
882 	if (unlikely(!skb->ignore_df && skb->len > mtu))
886 		if (IP6CB(skb)->frag_max_size > mtu)
890 		mtu = IP6CB(skb)->frag_max_size;
891 		if (mtu < IPV6_MIN_MTU)
892 			mtu = IPV6_MIN_MTU;
898 		if (frag_size && frag_size < mtu)
899 			mtu = frag_size;
901 	if (mtu < hlen + sizeof(struct frag_hdr) + 8)
903 	mtu -= hlen + sizeof(struct frag_hdr);
919 		if (first_len - hlen > mtu ||
927 			if (frag->len > mtu ||
1001 	ip6_frag_init(skb, hlen, mtu, rt->dst.dev->needed_tailroom,
1033 	icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1308 static void ip6_append_data_mtu(unsigned int *mtu,
1318 			*mtu = orig_mtu - rt->dst.header_len;
1325 			*mtu = orig_mtu;
1327 		*maxfraglen = ((*mtu - fragheaderlen) & ~7)
1337 	unsigned int mtu, frag_size;
1381 		mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
1382 		      READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst);
1384 		mtu = READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE ?
1385 			READ_ONCE(rt->dst.dev->mtu) : dst_mtu(xfrm_dst_path(&rt->dst));
1388 	if (frag_size && frag_size < mtu)
1389 		mtu = frag_size;
1391 	cork->base.fragsize = mtu;
1416 	unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu;
1440 	mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize;
1441 	orig_mtu = mtu;
1452 	if (mtu <= fragheaderlen ||
1453 	    ((mtu - fragheaderlen) & ~7) + fragheaderlen <= sizeof(struct frag_hdr))
1456 	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen -
1462 	if (headersize + transhdrlen > mtu)
1465 	if (cork->length + length > mtu - headersize && ipc6->dontfrag &&
1469 		ipv6_local_rxpmtu(sk, fl6, mtu - headersize +
1477 		maxnonfragsize = mtu;
1481 		pmtu = max_t(int, mtu - headersize + sizeof(struct ipv6hdr), 0);
1491 	    length <= mtu - headersize &&
1564 		copy = (cork->length <= mtu ? mtu : maxfraglen) - skb->len;
1581 			/* update mtu and maxfraglen if necessary */
1583 				ip6_append_data_mtu(&mtu, &maxfraglen,
1590 			 * If remaining data exceeds the mtu,
1595 			if (datalen > (cork->length <= mtu ? mtu : maxfraglen) - fragheaderlen)
1612 				alloclen = mtu;