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Release 4.11 net/ipv4/udp_offload.c

Directory: net/ipv4
/*
 *      IPV4 GSO/GRO offload support
 *      Linux INET 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.
 *
 *      UDPv4 GSO support
 */

#include <linux/skbuff.h>
#include <net/udp.h>
#include <net/protocol.h>


static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
	netdev_features_t features,
	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
					     netdev_features_t features),
	__be16 new_protocol, bool is_ipv6)
{
	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
	bool remcsum, need_csum, offload_csum, ufo, gso_partial;
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	struct udphdr *uh = udp_hdr(skb);
	u16 mac_offset = skb->mac_header;
	__be16 protocol = skb->protocol;
	u16 mac_len = skb->mac_len;
	int udp_offset, outer_hlen;
	__wsum partial;
	bool need_ipsec;

	if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
		goto out;

	/* Adjust partial header checksum to negate old length.
         * We cannot rely on the value contained in uh->len as it is
         * possible that the actual value exceeds the boundaries of the
         * 16 bit length field due to the header being added outside of an
         * IP or IPv6 frame that was already limited to 64K - 1.
         */
	if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
		partial = (__force __wsum)uh->len;
	else
		partial = (__force __wsum)htonl(skb->len);
	partial = csum_sub(csum_unfold(uh->check), partial);

	/* setup inner skb. */
	skb->encapsulation = 0;
	SKB_GSO_CB(skb)->encap_level = 0;
	__skb_pull(skb, tnl_hlen);
	skb_reset_mac_header(skb);
	skb_set_network_header(skb, skb_inner_network_offset(skb));
	skb->mac_len = skb_inner_network_offset(skb);
	skb->protocol = new_protocol;

	need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
	skb->encap_hdr_csum = need_csum;

	remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
	skb->remcsum_offload = remcsum;

	ufo = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);

	need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
	/* Try to offload checksum if possible */
	offload_csum = !!(need_csum &&
			  !need_ipsec &&
			  (skb->dev->features &
			   (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
				      (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));

	features &= skb->dev->hw_enc_features;

	/* The only checksum offload we care about from here on out is the
         * outer one so strip the existing checksum feature flags and
         * instead set the flag based on our outer checksum offload value.
         */
	if (remcsum || ufo) {
		features &= ~NETIF_F_CSUM_MASK;
		if (!need_csum || offload_csum)
			features |= NETIF_F_HW_CSUM;
	}

	/* segment inner packet. */
	segs = gso_inner_segment(skb, features);
	if (IS_ERR_OR_NULL(segs)) {
		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
				     mac_len);
		goto out;
	}

	gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);

	outer_hlen = skb_tnl_header_len(skb);
	udp_offset = outer_hlen - tnl_hlen;
	skb = segs;
	do {
		unsigned int len;

		if (remcsum)
			skb->ip_summed = CHECKSUM_NONE;

		/* Set up inner headers if we are offloading inner checksum */
		if (skb->ip_summed == CHECKSUM_PARTIAL) {
			skb_reset_inner_headers(skb);
			skb->encapsulation = 1;
		}

		skb->mac_len = mac_len;
		skb->protocol = protocol;

		__skb_push(skb, outer_hlen);
		skb_reset_mac_header(skb);
		skb_set_network_header(skb, mac_len);
		skb_set_transport_header(skb, udp_offset);
		len = skb->len - udp_offset;
		uh = udp_hdr(skb);

		/* If we are only performing partial GSO the inner header
                 * will be using a length value equal to only one MSS sized
                 * segment instead of the entire frame.
                 */
		if (gso_partial) {
			uh->len = htons(skb_shinfo(skb)->gso_size +
					SKB_GSO_CB(skb)->data_offset +
					skb->head - (unsigned char *)uh);
		} else {
			uh->len = htons(len);
		}

		if (!need_csum)
			continue;

		uh->check = ~csum_fold(csum_add(partial,
				       (__force __wsum)htonl(len)));

		if (skb->encapsulation || !offload_csum) {
			uh->check = gso_make_checksum(skb, ~uh->check);
			if (uh->check == 0)
				uh->check = CSUM_MANGLED_0;
		} else {
			skb->ip_summed = CHECKSUM_PARTIAL;
			skb->csum_start = skb_transport_header(skb) - skb->head;
			skb->csum_offset = offsetof(struct udphdr, check);
		}
	} while ((skb = skb->next));
out:
	return segs;
}


struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, netdev_features_t features, bool is_ipv6) { __be16 protocol = skb->protocol; const struct net_offload **offloads; const struct net_offload *ops; struct sk_buff *segs = ERR_PTR(-EINVAL); struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, netdev_features_t features); rcu_read_lock(); switch (skb->inner_protocol_type) { case ENCAP_TYPE_ETHER: protocol = skb->inner_protocol; gso_inner_segment = skb_mac_gso_segment; break; case ENCAP_TYPE_IPPROTO: offloads = is_ipv6 ? inet6_offloads : inet_offloads; ops = rcu_dereference(offloads[skb->inner_ipproto]); if (!ops || !ops->callbacks.gso_segment) goto out_unlock; gso_inner_segment = ops->callbacks.gso_segment; break; default: goto out_unlock; } segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment, protocol, is_ipv6); out_unlock: rcu_read_unlock(); return segs; }

Contributors

PersonTokensPropCommitsCommitProp
Tom Herbert165100.00%2100.00%
Total165100.00%2100.00%

EXPORT_SYMBOL(skb_udp_tunnel_segment);
static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, netdev_features_t features) { struct sk_buff *segs = ERR_PTR(-EINVAL); unsigned int mss; __wsum csum; struct udphdr *uh; struct iphdr *iph; if (skb->encapsulation && (skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) { segs = skb_udp_tunnel_segment(skb, features, false); goto out; } if (!pskb_may_pull(skb, sizeof(struct udphdr))) goto out; 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. */ skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); segs = NULL; goto out; } /* Do software UFO. Complete and fill in the UDP checksum as * HW cannot do checksum of UDP packets sent as multiple * IP fragments. */ uh = udp_hdr(skb); iph = ip_hdr(skb); uh->check = 0; csum = skb_checksum(skb, 0, skb->len, 0); uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum); if (uh->check == 0) uh->check = CSUM_MANGLED_0; skb->ip_summed = CHECKSUM_NONE; /* If there is no outer header we can fake a checksum offload * due to the fact that we have already done the checksum in * software prior to segmenting the frame. */ if (!skb->encap_hdr_csum) features |= NETIF_F_HW_CSUM; /* Fragment the skb. IP headers of the fragments are updated in * inet_gso_segment() */ segs = skb_segment(skb, features); out: return segs; }

Contributors

PersonTokensPropCommitsCommitProp
Daniel Borkmann13651.91%116.67%
Tom Herbert8030.53%350.00%
Wei-Chun Chao3412.98%116.67%
Alexander Duyck124.58%116.67%
Total262100.00%6100.00%


struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb, struct udphdr *uh, udp_lookup_t lookup) { struct sk_buff *p, **pp = NULL; struct udphdr *uh2; unsigned int off = skb_gro_offset(skb); int flush = 1; struct sock *sk; if (NAPI_GRO_CB(skb)->encap_mark || (skb->ip_summed != CHECKSUM_PARTIAL && NAPI_GRO_CB(skb)->csum_cnt == 0 && !NAPI_GRO_CB(skb)->csum_valid)) goto out; /* mark that this skb passed once through the tunnel gro layer */ NAPI_GRO_CB(skb)->encap_mark = 1; rcu_read_lock(); sk = (*lookup)(skb, uh->source, uh->dest); if (sk && udp_sk(sk)->gro_receive) goto unflush; goto out_unlock; unflush: flush = 0; for (p = *head; p; p = p->next) { if (!NAPI_GRO_CB(p)->same_flow) continue; uh2 = (struct udphdr *)(p->data + off); /* Match ports and either checksums are either both zero * or nonzero. */ if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) || (!uh->check ^ !uh2->check)) { NAPI_GRO_CB(p)->same_flow = 0; continue; } } skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr)); pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb); out_unlock: rcu_read_unlock(); out: NAPI_GRO_CB(skb)->flush |= flush; return pp; }

Contributors

PersonTokensPropCommitsCommitProp
Or Gerlitz21369.38%112.50%
Tom Herbert8527.69%450.00%
Jesse Gross30.98%112.50%
Sabrina Dubroca30.98%112.50%
Hannes Frederic Sowa30.98%112.50%
Total307100.00%8100.00%

EXPORT_SYMBOL(udp_gro_receive);
static struct sk_buff **udp4_gro_receive(struct sk_buff **head, struct sk_buff *skb) { struct udphdr *uh = udp_gro_udphdr(skb); if (unlikely(!uh)) goto flush; /* Don't bother verifying checksum if we're going to flush anyway. */ if (NAPI_GRO_CB(skb)->flush) goto skip; if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, inet_gro_compute_pseudo)) goto flush; else if (uh->check) skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check, inet_gro_compute_pseudo); skip: NAPI_GRO_CB(skb)->is_ipv6 = 0; return udp_gro_receive(head, skb, uh, udp4_lib_lookup_skb); flush: NAPI_GRO_CB(skb)->flush = 1; return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Tom Herbert12899.22%480.00%
Or Gerlitz10.78%120.00%
Total129100.00%5100.00%


int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup) { __be16 newlen = htons(skb->len - nhoff); struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); int err = -ENOSYS; struct sock *sk; uh->len = newlen; /* Set encapsulation before calling into inner gro_complete() functions * to make them set up the inner offsets. */ skb->encapsulation = 1; rcu_read_lock(); sk = (*lookup)(skb, uh->source, uh->dest); if (sk && udp_sk(sk)->gro_complete) err = udp_sk(sk)->gro_complete(sk, skb, nhoff + sizeof(struct udphdr)); rcu_read_unlock(); if (skb->remcsum_offload) skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM; return err; }

Contributors

PersonTokensPropCommitsCommitProp
Or Gerlitz8659.31%116.67%
Tom Herbert4933.79%350.00%
Jarno Rajahalme74.83%116.67%
Hannes Frederic Sowa32.07%116.67%
Total145100.00%6100.00%

EXPORT_SYMBOL(udp_gro_complete);
static int udp4_gro_complete(struct sk_buff *skb, int nhoff) { const struct iphdr *iph = ip_hdr(skb); struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); if (uh->check) { skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM; uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr, iph->daddr, 0); } else { skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL; } return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb); }

Contributors

PersonTokensPropCommitsCommitProp
Tom Herbert10599.06%375.00%
Eric Dumazet10.94%125.00%
Total106100.00%4100.00%

static const struct net_offload udpv4_offload = { .callbacks = { .gso_segment = udp4_ufo_fragment, .gro_receive = udp4_gro_receive, .gro_complete = udp4_gro_complete, }, };
int __init udpv4_offload_init(void) { return inet_add_offload(&udpv4_offload, IPPROTO_UDP); }

Contributors

PersonTokensPropCommitsCommitProp
Daniel Borkmann17100.00%1100.00%
Total17100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Tom Herbert101153.58%1544.12%
Or Gerlitz32317.12%12.94%
Alexander Duyck29315.53%823.53%
Daniel Borkmann1668.80%12.94%
Wei-Chun Chao341.80%12.94%
Ansis Atteka211.11%12.94%
Steffen Klassert180.95%12.94%
Jarno Rajahalme70.37%12.94%
Hannes Frederic Sowa60.32%12.94%
Sabrina Dubroca30.16%12.94%
Jesse Gross30.16%12.94%
Himangi Saraogi10.05%12.94%
Eric Dumazet10.05%12.94%
Total1887100.00%34100.00%
Directory: net/ipv4
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