--- /dev/null
+/*
+ * 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 DEFINE_SPINLOCK(udp_offload_lock);
+static struct udp_offload_priv __rcu *udp_offload_base __read_mostly;
+
+#define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock))
+
+struct udp_offload_priv {
+ struct udp_offload *offload;
+ struct rcu_head rcu;
+ struct udp_offload_priv __rcu *next;
+};
+
+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)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ u16 mac_offset = skb->mac_header;
+ int mac_len = skb->mac_len;
+ int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
+ __be16 protocol = skb->protocol;
+ netdev_features_t enc_features;
+ int udp_offset, outer_hlen;
+ unsigned int oldlen;
+ bool need_csum = !!(skb_shinfo(skb)->gso_type &
+ SKB_GSO_UDP_TUNNEL_CSUM);
+ bool remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
+ bool offload_csum = false, dont_encap = (need_csum || remcsum);
+
+ oldlen = (u16)~skb->len;
+
+ if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
+ goto out;
+
+ skb->encapsulation = 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;
+ skb->encap_hdr_csum = need_csum;
+ skb->remcsum_offload = remcsum;
+
+ /* Try to offload checksum if possible */
+ offload_csum = !!(need_csum &&
+ (skb->dev->features &
+ (is_ipv6 ? NETIF_F_V6_CSUM : NETIF_F_V4_CSUM)));
+
+ /* segment inner packet. */
+ enc_features = skb->dev->hw_enc_features & features;
+ segs = gso_inner_segment(skb, enc_features);
+ if (IS_ERR_OR_NULL(segs)) {
+ skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
+ mac_len);
+ goto out;
+ }
+
+ outer_hlen = skb_tnl_header_len(skb);
+ udp_offset = outer_hlen - tnl_hlen;
+ skb = segs;
+ do {
+ struct udphdr *uh;
+ int len;
+ __be32 delta;
+
+ if (dont_encap) {
+ skb->encapsulation = 0;
+ skb->ip_summed = CHECKSUM_NONE;
+ } else {
+ /* Only set up inner headers if we might be offloading
+ * inner checksum.
+ */
+ 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);
+ uh->len = htons(len);
+
+ if (!need_csum)
+ continue;
+
+ delta = htonl(oldlen + len);
+
+ uh->check = ~csum_fold((__force __wsum)
+ ((__force u32)uh->check +
+ (__force u32)delta));
+ if (offload_csum) {
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ } else if (remcsum) {
+ /* Need to calculate checksum from scratch,
+ * inner checksums are never when doing
+ * remote_checksum_offload.
+ */
+
+ skb->csum = skb_checksum(skb, udp_offset,
+ skb->len - udp_offset,
+ 0);
+ uh->check = csum_fold(skb->csum);
+ if (uh->check == 0)
+ uh->check = CSUM_MANGLED_0;
+ } else {
+ uh->check = gso_make_checksum(skb, ~uh->check);
+
+ if (uh->check == 0)
+ uh->check = CSUM_MANGLED_0;
+ }
+ } 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;
+}
+
+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. */
+ 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_TUNNEL_REMCSUM |
+ SKB_GSO_IPIP |
+ SKB_GSO_GRE | SKB_GSO_GRE_CSUM) ||
+ !(type & (SKB_GSO_UDP))))
+ goto out;
+
+ 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;
+
+ /* Fragment the skb. IP headers of the fragments are updated in
+ * inet_gso_segment()
+ */
+ segs = skb_segment(skb, features);
+out:
+ return segs;
+}
+
+int udp_add_offload(struct udp_offload *uo)
+{
+ struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC);
+
+ if (!new_offload)
+ return -ENOMEM;
+
+ new_offload->offload = uo;
+
+ spin_lock(&udp_offload_lock);
+ new_offload->next = udp_offload_base;
+ rcu_assign_pointer(udp_offload_base, new_offload);
+ spin_unlock(&udp_offload_lock);
+
+ return 0;
+}
+EXPORT_SYMBOL(udp_add_offload);
+
+static void udp_offload_free_routine(struct rcu_head *head)
+{
+ struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
+ kfree(ou_priv);
+}
+
+void udp_del_offload(struct udp_offload *uo)
+{
+ struct udp_offload_priv __rcu **head = &udp_offload_base;
+ struct udp_offload_priv *uo_priv;
+
+ spin_lock(&udp_offload_lock);
+
+ uo_priv = udp_deref_protected(*head);
+ for (; uo_priv != NULL;
+ uo_priv = udp_deref_protected(*head)) {
+ if (uo_priv->offload == uo) {
+ rcu_assign_pointer(*head,
+ udp_deref_protected(uo_priv->next));
+ goto unlock;
+ }
+ head = &uo_priv->next;
+ }
+ pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
+unlock:
+ spin_unlock(&udp_offload_lock);
+ if (uo_priv)
+ call_rcu(&uo_priv->rcu, udp_offload_free_routine);
+}
+EXPORT_SYMBOL(udp_del_offload);
+
+struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
+ struct udphdr *uh)
+{
+ struct udp_offload_priv *uo_priv;
+ struct sk_buff *p, **pp = NULL;
+ struct udphdr *uh2;
+ unsigned int off = skb_gro_offset(skb);
+ int flush = 1;
+
+ if (NAPI_GRO_CB(skb)->udp_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 udp gro layer */
+ NAPI_GRO_CB(skb)->udp_mark = 1;
+
+ rcu_read_lock();
+ uo_priv = rcu_dereference(udp_offload_base);
+ for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
+ if (uo_priv->offload->port == uh->dest &&
+ uo_priv->offload->callbacks.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));
+ NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto;
+ pp = uo_priv->offload->callbacks.gro_receive(head, skb,
+ uo_priv->offload);
+
+out_unlock:
+ rcu_read_unlock();
+out:
+ NAPI_GRO_CB(skb)->flush |= flush;
+ return pp;
+}
+
+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);
+
+flush:
+ NAPI_GRO_CB(skb)->flush = 1;
+ return NULL;
+}
+
+int udp_gro_complete(struct sk_buff *skb, int nhoff)
+{
+ struct udp_offload_priv *uo_priv;
+ __be16 newlen = htons(skb->len - nhoff);
+ struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
+ int err = -ENOSYS;
+
+ uh->len = newlen;
+
+ rcu_read_lock();
+
+ uo_priv = rcu_dereference(udp_offload_base);
+ for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
+ if (uo_priv->offload->port == uh->dest &&
+ uo_priv->offload->callbacks.gro_complete)
+ break;
+ }
+
+ if (uo_priv) {
+ NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto;
+ err = uo_priv->offload->callbacks.gro_complete(skb,
+ nhoff + sizeof(struct udphdr),
+ uo_priv->offload);
+ }
+
+ rcu_read_unlock();
+
+ if (skb->remcsum_offload)
+ skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
+
+ skb->encapsulation = 1;
+ skb_set_inner_mac_header(skb, nhoff + sizeof(struct udphdr));
+
+ return err;
+}
+
+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);
+}
+
+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);
+}
Code Review / kvmfornfv.git / blobdiff