[mirror_ubuntu-zesty-kernel.git] / net / ipv6 / udp_offload.c

/*
 *	IPV6 GSO/GRO offload support
 *	Linux INET6 implementation
 *
 *	This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 *
 *      UDPv6 GSO support
 */
#include <linux/skbuff.h>
#include <net/protocol.h>
#include <net/ipv6.h>
#include <net/udp.h>
#include <net/ip6_checksum.h>
#include "ip6_offload.h"

static int udp6_ufo_send_check(struct sk_buff *skb)
{
	const struct ipv6hdr *ipv6h;
	struct udphdr *uh;

	if (!pskb_may_pull(skb, sizeof(*uh)))
		return -EINVAL;

	if (likely(!skb->encapsulation)) {
		ipv6h = ipv6_hdr(skb);
		uh = udp_hdr(skb);

		uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
					     IPPROTO_UDP, 0);
		skb->csum_start = skb_transport_header(skb) - skb->head;
		skb->csum_offset = offsetof(struct udphdr, check);
		skb->ip_summed = CHECKSUM_PARTIAL;
	}

	return 0;
}

static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
					 netdev_features_t features)
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	unsigned int mss;
	unsigned int unfrag_ip6hlen, unfrag_len;
	struct frag_hdr *fptr;
	u8 *packet_start, *prevhdr;
	u8 nexthdr;
	u8 frag_hdr_sz = sizeof(struct frag_hdr);
	int offset;
	__wsum csum;
	int tnl_hlen;

	mss = skb_shinfo(skb)->gso_size;
	if (unlikely(skb->len <= mss))
		goto out;

	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
		/* Packet is from an untrusted source, reset gso_segs. */
		int type = skb_shinfo(skb)->gso_type;

		if (unlikely(type & ~(SKB_GSO_UDP |
				      SKB_GSO_DODGY |
				      SKB_GSO_UDP_TUNNEL |
				      SKB_GSO_UDP_TUNNEL_CSUM |
				      SKB_GSO_GRE |
				      SKB_GSO_GRE_CSUM |
				      SKB_GSO_IPIP |
				      SKB_GSO_SIT |
				      SKB_GSO_MPLS) ||
			     !(type & (SKB_GSO_UDP))))
			goto out;

		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);

		segs = NULL;
		goto out;
	}

	if (skb->encapsulation && skb_shinfo(skb)->gso_type &
	    (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
		segs = skb_udp_tunnel_segment(skb, features);
	else {
		/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
		 * do checksum of UDP packets sent as multiple IP fragments.
		 */
		offset = skb_checksum_start_offset(skb);
		csum = skb_checksum(skb, offset, skb->len - offset, 0);
		offset += skb->csum_offset;
		*(__sum16 *)(skb->data + offset) = csum_fold(csum);
		skb->ip_summed = CHECKSUM_NONE;

		/* Check if there is enough headroom to insert fragment header. */
		tnl_hlen = skb_tnl_header_len(skb);
		if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
			if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
				goto out;
		}

		/* Find the unfragmentable header and shift it left by frag_hdr_sz
		 * bytes to insert fragment header.
		 */
		unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
		nexthdr = *prevhdr;
		*prevhdr = NEXTHDR_FRAGMENT;
		unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
			     unfrag_ip6hlen + tnl_hlen;
		packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
		memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);

		SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
		skb->mac_header -= frag_hdr_sz;
		skb->network_header -= frag_hdr_sz;

		fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
		fptr->nexthdr = nexthdr;
		fptr->reserved = 0;
		fptr->identification = skb_shinfo(skb)->ip6_frag_id;

		/* Fragment the skb. ipv6 header and the remaining fields of the
		 * fragment header are updated in ipv6_gso_segment()
		 */
		segs = skb_segment(skb, features);
	}

out:
	return segs;
}
static const struct net_offload udpv6_offload = {
	.callbacks = {
		.gso_send_check =	udp6_ufo_send_check,
		.gso_segment	=	udp6_ufo_fragment,
	},
};

int __init udp_offload_init(void)
{
	return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
}
Commit	Line	Data
5edbb07d VY	1	/*
	2	* IPV6 GSO/GRO offload support
	3	* Linux INET6 implementation
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version
	8	* 2 of the License, or (at your option) any later version.
	9	*
	10	* UDPv6 GSO support
	11	*/
	12	#include <linux/skbuff.h>
	13	#include <net/protocol.h>
	14	#include <net/ipv6.h>
	15	#include <net/udp.h>
d4d0d355	16	#include <net/ip6_checksum.h>
5edbb07d VY	17	#include "ip6_offload.h"
	18
	19	static int udp6_ufo_send_check(struct sk_buff *skb)
	20	{
	21	const struct ipv6hdr *ipv6h;
	22	struct udphdr *uh;
	23
	24	if (!pskb_may_pull(skb, sizeof(*uh)))
	25	return -EINVAL;
	26
d949d826 CW	27	if (likely(!skb->encapsulation)) {
	28	ipv6h = ipv6_hdr(skb);
	29	uh = udp_hdr(skb);
	30
	31	uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
	32	IPPROTO_UDP, 0);
	33	skb->csum_start = skb_transport_header(skb) - skb->head;
	34	skb->csum_offset = offsetof(struct udphdr, check);
	35	skb->ip_summed = CHECKSUM_PARTIAL;
	36	}
5edbb07d	37
5edbb07d VY	38	return 0;
	39	}
	40
	41	static struct sk_buff udp6_ufo_fragment(struct sk_buff skb,
d949d826	42	netdev_features_t features)
5edbb07d VY	43	{
	44	struct sk_buff *segs = ERR_PTR(-EINVAL);
	45	unsigned int mss;
	46	unsigned int unfrag_ip6hlen, unfrag_len;
	47	struct frag_hdr *fptr;
1e2bd517	48	u8 packet_start, prevhdr;
5edbb07d VY	49	u8 nexthdr;
	50	u8 frag_hdr_sz = sizeof(struct frag_hdr);
	51	int offset;
	52	__wsum csum;
1e2bd517	53	int tnl_hlen;
5edbb07d VY	54
	55	mss = skb_shinfo(skb)->gso_size;
	56	if (unlikely(skb->len <= mss))
	57	goto out;
	58
	59	if (skb_gso_ok(skb, features \| NETIF_F_GSO_ROBUST)) {
	60	/* Packet is from an untrusted source, reset gso_segs. */
	61	int type = skb_shinfo(skb)->gso_type;
	62
73136267 PS	63	if (unlikely(type & ~(SKB_GSO_UDP \|
	64	SKB_GSO_DODGY \|
	65	SKB_GSO_UDP_TUNNEL \|
0f4f4ffa	66	SKB_GSO_UDP_TUNNEL_CSUM \|
0d89d203	67	SKB_GSO_GRE \|
4749c09c	68	SKB_GSO_GRE_CSUM \|
cb32f511	69	SKB_GSO_IPIP \|
61c1db7f	70	SKB_GSO_SIT \|
0d89d203	71	SKB_GSO_MPLS) \|\|
5edbb07d VY	72	!(type & (SKB_GSO_UDP))))
	73	goto out;
	74
	75	skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
	76
	77	segs = NULL;
	78	goto out;
	79	}
	80
0f4f4ffa TH	81	if (skb->encapsulation && skb_shinfo(skb)->gso_type &
0f4f4ffa TH	82	(SKB_GSO_UDP_TUNNEL\|SKB_GSO_UDP_TUNNEL_CSUM))
eb3c0d83	83	segs = skb_udp_tunnel_segment(skb, features);
d949d826 CW	84	else {
	85	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
	86	* do checksum of UDP packets sent as multiple IP fragments.
	87	*/
	88	offset = skb_checksum_start_offset(skb);
	89	csum = skb_checksum(skb, offset, skb->len - offset, 0);
	90	offset += skb->csum_offset;
	91	(__sum16 )(skb->data + offset) = csum_fold(csum);
	92	skb->ip_summed = CHECKSUM_NONE;
	93
	94	/* Check if there is enough headroom to insert fragment header. */
	95	tnl_hlen = skb_tnl_header_len(skb);
0e033e04	96	if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
d949d826 CW	97	if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
	98	goto out;
	99	}
	100
	101	/* Find the unfragmentable header and shift it left by frag_hdr_sz
	102	* bytes to insert fragment header.
	103	*/
	104	unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
	105	nexthdr = *prevhdr;
	106	*prevhdr = NEXTHDR_FRAGMENT;
	107	unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
	108	unfrag_ip6hlen + tnl_hlen;
	109	packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
	110	memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
	111
	112	SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
	113	skb->mac_header -= frag_hdr_sz;
	114	skb->network_header -= frag_hdr_sz;
	115
	116	fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
	117	fptr->nexthdr = nexthdr;
	118	fptr->reserved = 0;
916e4cf4	119	fptr->identification = skb_shinfo(skb)->ip6_frag_id;
d949d826 CW	120
	121	/* Fragment the skb. ipv6 header and the remaining fields of the
	122	* fragment header are updated in ipv6_gso_segment()
	123	*/
	124	segs = skb_segment(skb, features);
1e2bd517	125	}
5edbb07d	126
5edbb07d VY	127	out:
	128	return segs;
	129	}
	130	static const struct net_offload udpv6_offload = {
f191a1d1 VY	131	.callbacks = {
	132	.gso_send_check = udp6_ufo_send_check,
	133	.gso_segment = udp6_ufo_fragment,
	134	},
5edbb07d VY	135	};
	136
	137	int __init udp_offload_init(void)
	138	{
	139	return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
	140	}