gue: Receive side for Generic UDP Encapsulation

This patch adds support receiving for GUE packets in the fou module. The
fou module now supports direct foo-over-udp (no encapsulation header)
and GUE. To support this a type parameter is added to the fou netlink
parameters.

For a GUE socket we define gue_udp_recv, gue_gro_receive, and
gue_gro_complete to handle the specifics of the GUE protocol. Most
of the code to manage and configure sockets is common with the fou.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/gue.h b/include/net/gue.h
new file mode 100644 (file)
index 0000000..b6c3327
--- /dev/null
+++ b/include/net/gue.h
@@ -0,0 +1,23 @@
+#ifndef __NET_GUE_H
+#define __NET_GUE_H
+
+struct guehdr {
+       union {
+               struct {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+                       __u8    hlen:4,
+                       version:4;
+#elif defined (__BIG_ENDIAN_BITFIELD)
+                       __u8    version:4,
+                               hlen:4;
+#else
+#error  "Please fix <asm/byteorder.h>"
+#endif
+                       __u8    next_hdr;
+                       __u16   flags;
+               };
+               __u32 word;
+       };
+};
+
+#endif

diff --git a/include/uapi/linux/fou.h b/include/uapi/linux/fou.h
index e03376de453d3deab71b382325e65cc51673a34d..8df06894da23dac0233bc8e7b0da28b693aba20f 100644 (file)
--- a/include/uapi/linux/fou.h
+++ b/include/uapi/linux/fou.h
@@ -13,6 +13,7 @@ enum {
        FOU_ATTR_PORT,                          /* u16 */
        FOU_ATTR_AF,                            /* u8 */
        FOU_ATTR_IPPROTO,                       /* u8 */
+       FOU_ATTR_TYPE,                          /* u8 */
 
        __FOU_ATTR_MAX,
 };
@@ -27,6 +28,12 @@ enum {
        __FOU_CMD_MAX,
 };
 
+enum {
+       FOU_ENCAP_UNSPEC,
+       FOU_ENCAP_DIRECT,
+       FOU_ENCAP_GUE,
+};
+
 #define FOU_CMD_MAX    (__FOU_CMD_MAX - 1)
 
 #endif /* _UAPI_LINUX_FOU_H */

diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 7e2126a31f2e9b963afc51a4dbd553fb2fc8574c..efa70ad44906aac3204cd90e76b35c3159caa2ac 100644 (file)
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -7,6 +7,7 @@
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <net/genetlink.h>
+#include <net/gue.h>
 #include <net/ip.h>
 #include <net/protocol.h>
 #include <net/udp.h>
@@ -27,6 +28,7 @@ struct fou {
 };
 
 struct fou_cfg {
+       u16 type;
        u8 protocol;
        struct udp_port_cfg udp_config;
 };
@@ -64,6 +66,41 @@ static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
                                          sizeof(struct udphdr));
 }
 
+static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
+{
+       struct fou *fou = fou_from_sock(sk);
+       size_t len;
+       struct guehdr *guehdr;
+       struct udphdr *uh;
+
+       if (!fou)
+               return 1;
+
+       len = sizeof(struct udphdr) + sizeof(struct guehdr);
+       if (!pskb_may_pull(skb, len))
+               goto drop;
+
+       uh = udp_hdr(skb);
+       guehdr = (struct guehdr *)&uh[1];
+
+       len += guehdr->hlen << 2;
+       if (!pskb_may_pull(skb, len))
+               goto drop;
+
+       if (guehdr->version != 0)
+               goto drop;
+
+       if (guehdr->flags) {
+               /* No support yet */
+               goto drop;
+       }
+
+       return fou_udp_encap_recv_deliver(skb, guehdr->next_hdr, len);
+drop:
+       kfree_skb(skb);
+       return 0;
+}
+
 static struct sk_buff **fou_gro_receive(struct sk_buff **head,
                                        struct sk_buff *skb)
 {
@@ -107,6 +144,112 @@ out_unlock:
        return err;
 }
 
+static struct sk_buff **gue_gro_receive(struct sk_buff **head,
+                                       struct sk_buff *skb)
+{
+       const struct net_offload **offloads;
+       const struct net_offload *ops;
+       struct sk_buff **pp = NULL;
+       struct sk_buff *p;
+       u8 proto;
+       struct guehdr *guehdr;
+       unsigned int hlen, guehlen;
+       unsigned int off;
+       int flush = 1;
+
+       off = skb_gro_offset(skb);
+       hlen = off + sizeof(*guehdr);
+       guehdr = skb_gro_header_fast(skb, off);
+       if (skb_gro_header_hard(skb, hlen)) {
+               guehdr = skb_gro_header_slow(skb, hlen, off);
+               if (unlikely(!guehdr))
+                       goto out;
+       }
+
+       proto = guehdr->next_hdr;
+
+       rcu_read_lock();
+       offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+       ops = rcu_dereference(offloads[proto]);
+       if (WARN_ON(!ops || !ops->callbacks.gro_receive))
+               goto out_unlock;
+
+       guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
+
+       hlen = off + guehlen;
+       if (skb_gro_header_hard(skb, hlen)) {
+               guehdr = skb_gro_header_slow(skb, hlen, off);
+               if (unlikely(!guehdr))
+                       goto out_unlock;
+       }
+
+       flush = 0;
+
+       for (p = *head; p; p = p->next) {
+               const struct guehdr *guehdr2;
+
+               if (!NAPI_GRO_CB(p)->same_flow)
+                       continue;
+
+               guehdr2 = (struct guehdr *)(p->data + off);
+
+               /* Compare base GUE header to be equal (covers
+                * hlen, version, next_hdr, and flags.
+                */
+               if (guehdr->word != guehdr2->word) {
+                       NAPI_GRO_CB(p)->same_flow = 0;
+                       continue;
+               }
+
+               /* Compare optional fields are the same. */
+               if (guehdr->hlen && memcmp(&guehdr[1], &guehdr2[1],
+                                          guehdr->hlen << 2)) {
+                       NAPI_GRO_CB(p)->same_flow = 0;
+                       continue;
+               }
+       }
+
+       skb_gro_pull(skb, guehlen);
+
+       /* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
+       skb_gro_postpull_rcsum(skb, guehdr, guehlen);
+
+       pp = ops->callbacks.gro_receive(head, skb);
+
+out_unlock:
+       rcu_read_unlock();
+out:
+       NAPI_GRO_CB(skb)->flush |= flush;
+
+       return pp;
+}
+
+static int gue_gro_complete(struct sk_buff *skb, int nhoff)
+{
+       const struct net_offload **offloads;
+       struct guehdr *guehdr = (struct guehdr *)(skb->data + nhoff);
+       const struct net_offload *ops;
+       unsigned int guehlen;
+       u8 proto;
+       int err = -ENOENT;
+
+       proto = guehdr->next_hdr;
+
+       guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
+
+       rcu_read_lock();
+       offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+       ops = rcu_dereference(offloads[proto]);
+       if (WARN_ON(!ops || !ops->callbacks.gro_complete))
+               goto out_unlock;
+
+       err = ops->callbacks.gro_complete(skb, nhoff + guehlen);
+
+out_unlock:
+       rcu_read_unlock();
+       return err;
+}
+
 static int fou_add_to_port_list(struct fou *fou)
 {
        struct fou *fout;
@@ -142,6 +285,28 @@ static void fou_release(struct fou *fou)
        kfree(fou);
 }
 
+static int fou_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
+{
+       udp_sk(sk)->encap_rcv = fou_udp_recv;
+       fou->protocol = cfg->protocol;
+       fou->udp_offloads.callbacks.gro_receive = fou_gro_receive;
+       fou->udp_offloads.callbacks.gro_complete = fou_gro_complete;
+       fou->udp_offloads.port = cfg->udp_config.local_udp_port;
+       fou->udp_offloads.ipproto = cfg->protocol;
+
+       return 0;
+}
+
+static int gue_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
+{
+       udp_sk(sk)->encap_rcv = gue_udp_recv;
+       fou->udp_offloads.callbacks.gro_receive = gue_gro_receive;
+       fou->udp_offloads.callbacks.gro_complete = gue_gro_complete;
+       fou->udp_offloads.port = cfg->udp_config.local_udp_port;
+
+       return 0;
+}
+
 static int fou_create(struct net *net, struct fou_cfg *cfg,
                      struct socket **sockp)
 {
@@ -164,10 +329,24 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
 
        sk = sock->sk;
 
-       /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
-       fou->protocol = cfg->protocol;
-       fou->port =  cfg->udp_config.local_udp_port;
-       udp_sk(sk)->encap_rcv = fou_udp_recv;
+       fou->port = cfg->udp_config.local_udp_port;
+
+       /* Initial for fou type */
+       switch (cfg->type) {
+       case FOU_ENCAP_DIRECT:
+               err = fou_encap_init(sk, fou, cfg);
+               if (err)
+                       goto error;
+               break;
+       case FOU_ENCAP_GUE:
+               err = gue_encap_init(sk, fou, cfg);
+               if (err)
+                       goto error;
+               break;
+       default:
+               err = -EINVAL;
+               goto error;
+       }
 
        udp_sk(sk)->encap_type = 1;
        udp_encap_enable();
@@ -179,11 +358,6 @@ static int fou_create(struct net *net, struct fou_cfg *cfg,
 
        sk->sk_allocation = GFP_ATOMIC;
 
-       fou->udp_offloads.callbacks.gro_receive = fou_gro_receive;
-       fou->udp_offloads.callbacks.gro_complete = fou_gro_complete;
-       fou->udp_offloads.port = cfg->udp_config.local_udp_port;
-       fou->udp_offloads.ipproto = cfg->protocol;
-
        if (cfg->udp_config.family == AF_INET) {
                err = udp_add_offload(&fou->udp_offloads);
                if (err)
@@ -240,6 +414,7 @@ static struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
        [FOU_ATTR_PORT] = { .type = NLA_U16, },
        [FOU_ATTR_AF] = { .type = NLA_U8, },
        [FOU_ATTR_IPPROTO] = { .type = NLA_U8, },
+       [FOU_ATTR_TYPE] = { .type = NLA_U8, },
 };
 
 static int parse_nl_config(struct genl_info *info,
@@ -267,6 +442,9 @@ static int parse_nl_config(struct genl_info *info,
        if (info->attrs[FOU_ATTR_IPPROTO])
                cfg->protocol = nla_get_u8(info->attrs[FOU_ATTR_IPPROTO]);
 
+       if (info->attrs[FOU_ATTR_TYPE])
+               cfg->type = nla_get_u8(info->attrs[FOU_ATTR_TYPE]);
+
        return 0;
 }