251 lines
6.2 KiB
C
251 lines
6.2 KiB
C
/*
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* IPV4 GSO/GRO offload support
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* Linux INET implementation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* UDPv4 GSO support
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*/
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#include <linux/skbuff.h>
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#include <net/udp.h>
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#include <net/protocol.h>
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static DEFINE_SPINLOCK(udp_offload_lock);
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static struct udp_offload_priv __rcu *udp_offload_base __read_mostly;
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#define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock))
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struct udp_offload_priv {
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struct udp_offload *offload;
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struct rcu_head rcu;
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struct udp_offload_priv __rcu *next;
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};
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static int udp4_ufo_send_check(struct sk_buff *skb)
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{
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if (!pskb_may_pull(skb, sizeof(struct udphdr)))
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return -EINVAL;
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if (likely(!skb->encapsulation)) {
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const struct iphdr *iph;
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struct udphdr *uh;
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iph = ip_hdr(skb);
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uh = udp_hdr(skb);
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uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
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IPPROTO_UDP, 0);
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct udphdr, check);
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skb->ip_summed = CHECKSUM_PARTIAL;
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}
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return 0;
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}
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static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
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netdev_features_t features)
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{
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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unsigned int mss;
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int offset;
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__wsum csum;
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if (skb->encapsulation &&
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(skb_shinfo(skb)->gso_type &
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(SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
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segs = skb_udp_tunnel_segment(skb, features);
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goto out;
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}
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mss = skb_shinfo(skb)->gso_size;
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if (unlikely(skb->len <= mss))
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goto out;
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if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
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/* Packet is from an untrusted source, reset gso_segs. */
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int type = skb_shinfo(skb)->gso_type;
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if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
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SKB_GSO_UDP_TUNNEL |
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SKB_GSO_UDP_TUNNEL_CSUM |
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SKB_GSO_IPIP |
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SKB_GSO_GRE | SKB_GSO_GRE_CSUM |
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SKB_GSO_MPLS) ||
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!(type & (SKB_GSO_UDP))))
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goto out;
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skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
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segs = NULL;
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goto out;
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}
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/* Do software UFO. Complete and fill in the UDP checksum as
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* HW cannot do checksum of UDP packets sent as multiple
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* IP fragments.
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*/
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offset = skb_checksum_start_offset(skb);
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csum = skb_checksum(skb, offset, skb->len - offset, 0);
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offset += skb->csum_offset;
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*(__sum16 *)(skb->data + offset) = csum_fold(csum);
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skb->ip_summed = CHECKSUM_NONE;
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/* Fragment the skb. IP headers of the fragments are updated in
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* inet_gso_segment()
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*/
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segs = skb_segment(skb, features);
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out:
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return segs;
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}
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int udp_add_offload(struct udp_offload *uo)
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{
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struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC);
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if (!new_offload)
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return -ENOMEM;
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new_offload->offload = uo;
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spin_lock(&udp_offload_lock);
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new_offload->next = udp_offload_base;
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rcu_assign_pointer(udp_offload_base, new_offload);
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spin_unlock(&udp_offload_lock);
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return 0;
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}
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EXPORT_SYMBOL(udp_add_offload);
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static void udp_offload_free_routine(struct rcu_head *head)
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{
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struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
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kfree(ou_priv);
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}
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void udp_del_offload(struct udp_offload *uo)
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{
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struct udp_offload_priv __rcu **head = &udp_offload_base;
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struct udp_offload_priv *uo_priv;
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spin_lock(&udp_offload_lock);
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uo_priv = udp_deref_protected(*head);
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for (; uo_priv != NULL;
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uo_priv = udp_deref_protected(*head)) {
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if (uo_priv->offload == uo) {
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rcu_assign_pointer(*head,
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udp_deref_protected(uo_priv->next));
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goto unlock;
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}
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head = &uo_priv->next;
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}
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pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
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unlock:
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spin_unlock(&udp_offload_lock);
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if (uo_priv != NULL)
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call_rcu(&uo_priv->rcu, udp_offload_free_routine);
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}
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EXPORT_SYMBOL(udp_del_offload);
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static struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb)
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{
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struct udp_offload_priv *uo_priv;
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struct sk_buff *p, **pp = NULL;
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struct udphdr *uh, *uh2;
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unsigned int hlen, off;
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int flush = 1;
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if (NAPI_GRO_CB(skb)->udp_mark ||
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(!skb->encapsulation && skb->ip_summed != CHECKSUM_COMPLETE))
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goto out;
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/* mark that this skb passed once through the udp gro layer */
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NAPI_GRO_CB(skb)->udp_mark = 1;
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off = skb_gro_offset(skb);
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hlen = off + sizeof(*uh);
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uh = skb_gro_header_fast(skb, off);
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if (skb_gro_header_hard(skb, hlen)) {
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uh = skb_gro_header_slow(skb, hlen, off);
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if (unlikely(!uh))
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goto out;
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}
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rcu_read_lock();
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uo_priv = rcu_dereference(udp_offload_base);
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for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
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if (uo_priv->offload->port == uh->dest &&
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uo_priv->offload->callbacks.gro_receive)
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goto unflush;
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}
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goto out_unlock;
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unflush:
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flush = 0;
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for (p = *head; p; p = p->next) {
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if (!NAPI_GRO_CB(p)->same_flow)
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continue;
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uh2 = (struct udphdr *)(p->data + off);
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if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
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NAPI_GRO_CB(p)->same_flow = 0;
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continue;
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}
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}
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skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
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skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
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pp = uo_priv->offload->callbacks.gro_receive(head, skb);
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out_unlock:
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rcu_read_unlock();
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out:
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NAPI_GRO_CB(skb)->flush |= flush;
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return pp;
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}
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static int udp_gro_complete(struct sk_buff *skb, int nhoff)
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{
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struct udp_offload_priv *uo_priv;
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__be16 newlen = htons(skb->len - nhoff);
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struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
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int err = -ENOSYS;
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uh->len = newlen;
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rcu_read_lock();
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uo_priv = rcu_dereference(udp_offload_base);
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for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
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if (uo_priv->offload->port == uh->dest &&
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uo_priv->offload->callbacks.gro_complete)
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break;
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}
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if (uo_priv != NULL)
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err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));
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rcu_read_unlock();
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return err;
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}
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static const struct net_offload udpv4_offload = {
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.callbacks = {
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.gso_send_check = udp4_ufo_send_check,
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.gso_segment = udp4_ufo_fragment,
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.gro_receive = udp_gro_receive,
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.gro_complete = udp_gro_complete,
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},
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};
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int __init udpv4_offload_init(void)
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{
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return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
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}
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