tcp: introduce __tcp_fastopen_cookie_gen_cipher()

Restructure __tcp_fastopen_cookie_gen() to take a 'struct crypto_cipher'
argument and rename it as __tcp_fastopen_cookie_gen_cipher(). Subsequent
patches will provide different ciphers based on which key is being used for
the cookie generation.

Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 36 deletions

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 018a48477355..3889ad28dd06 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -111,25 +111,38 @@ error:		kfree(ctx);
         return err;
 }
 
-static bool __tcp_fastopen_cookie_gen(struct sock *sk, const void *path,
-                                      struct tcp_fastopen_cookie *foc)
+static bool __tcp_fastopen_cookie_gen_cipher(struct request_sock *req,
+                                             struct sk_buff *syn,
+                                             struct crypto_cipher *tfm,
+                                             struct tcp_fastopen_cookie *foc)
 {
-        struct tcp_fastopen_context *ctx;
-        bool ok = false;
-
-        rcu_read_lock();
+        if (req->rsk_ops->family == AF_INET) {
+                const struct iphdr *iph = ip_hdr(syn);
+                __be32 path[4] = { iph->saddr, iph->daddr, 0, 0 };
 
-        ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx);
-        if (!ctx)
-                ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx);
+                crypto_cipher_encrypt_one(tfm, foc->val, (void *)path);
+                foc->len = TCP_FASTOPEN_COOKIE_SIZE;
+                return true;
+        }
 
-        if (ctx) {
-                crypto_cipher_encrypt_one(ctx->tfm, foc->val, path);
+#if IS_ENABLED(CONFIG_IPV6)
+        if (req->rsk_ops->family == AF_INET6) {
+                const struct ipv6hdr *ip6h = ipv6_hdr(syn);
+                struct tcp_fastopen_cookie tmp;
+                struct in6_addr *buf;
+                int i;
+
+                crypto_cipher_encrypt_one(tfm, tmp.val,
+                                          (void *)&ip6h->saddr);
+                buf = &tmp.addr;
+                for (i = 0; i < 4; i++)
+                        buf->s6_addr32[i] ^= ip6h->daddr.s6_addr32[i];
+                crypto_cipher_encrypt_one(tfm, foc->val, (void *)buf);
                 foc->len = TCP_FASTOPEN_COOKIE_SIZE;
-                ok = true;
+                return true;
         }
-        rcu_read_unlock();
-        return ok;
+#endif
+        return false;
 }
 
 /* Generate the fastopen cookie by doing aes128 encryption on both
@@ -143,29 +156,17 @@ static bool tcp_fastopen_cookie_gen(struct sock *sk,
                                     struct sk_buff *syn,
                                     struct tcp_fastopen_cookie *foc)
 {
-        if (req->rsk_ops->family == AF_INET) {
-                const struct iphdr *iph = ip_hdr(syn);
-
-                __be32 path[4] = { iph->saddr, iph->daddr, 0, 0 };
-                return __tcp_fastopen_cookie_gen(sk, path, foc);
-        }
-
-#if IS_ENABLED(CONFIG_IPV6)
-        if (req->rsk_ops->family == AF_INET6) {
-                const struct ipv6hdr *ip6h = ipv6_hdr(syn);
-                struct tcp_fastopen_cookie tmp;
-
-                if (__tcp_fastopen_cookie_gen(sk, &ip6h->saddr, &tmp)) {
-                        struct in6_addr *buf = &tmp.addr;
-                        int i;
+        struct tcp_fastopen_context *ctx;
+        bool ok = false;
 
-                        for (i = 0; i < 4; i++)
-                                buf->s6_addr32[i] ^= ip6h->daddr.s6_addr32[i];
-                        return __tcp_fastopen_cookie_gen(sk, buf, foc);
-                }
-        }
-#endif
-        return false;
+        rcu_read_lock();
+        ctx = rcu_dereference(inet_csk(sk)->icsk_accept_queue.fastopenq.ctx);
+        if (!ctx)
+                ctx = rcu_dereference(sock_net(sk)->ipv4.tcp_fastopen_ctx);
+        if (ctx)
+                ok = __tcp_fastopen_cookie_gen_cipher(req, syn, ctx->tfm, foc);
+        rcu_read_unlock();
+        return ok;
 }