tcp md5sig: Let the caller pass appropriate key for tcp_v{4,6}_do_calc_md5_hash().

As we do for other socket/timewait-socket specific parameters,
let the callers pass appropriate arguments to
tcp_v{4,6}_do_calc_md5_hash().

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

3 files changed, 42 insertions, 51 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index eac26b73bcc3..07005ebb47a7 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1142,6 +1142,16 @@ extern int			tcp_v4_md5_do_add(struct sock *sk,
 extern int                      tcp_v4_md5_do_del(struct sock *sk,
                                                   __be32 addr);
 
+#ifdef CONFIG_TCP_MD5SIG
+#define tcp_twsk_md5_key(twsk)  ((twsk)->tw_md5_keylen ?                 \
+                                 &(struct tcp_md5sig_key) {              \
+                                        .key = (twsk)->tw_md5_key,       \
+                                        .keylen = (twsk)->tw_md5_keylen, \
+                                } : NULL)
+#else
+#define tcp_twsk_md5_key(twsk)  NULL
+#endif
+
 extern struct tcp_md5sig_pool   **tcp_alloc_md5sig_pool(void);
 extern void                     tcp_free_md5sig_pool(void);
 
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index e331cdbd0953..f7ff2a64a7f0 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -96,6 +96,12 @@ static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
 static int tcp_v4_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
                                    __be32 saddr, __be32 daddr,
                                    struct tcphdr *th, unsigned int tcplen);
+#else
+static inline
+struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
+{
+        return NULL;
+}
 #endif
 
 struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
@@ -604,9 +610,9 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
    outside socket context is ugly, certainly. What can I do?
  */
 
-static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
-                            struct sk_buff *skb, u32 seq, u32 ack,
-                            u32 win, u32 ts)
+static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
+                            u32 win, u32 ts, int oif,
+                            struct tcp_md5sig_key *key)
 {
         struct tcphdr *th = tcp_hdr(skb);
         struct {
@@ -618,10 +624,6 @@ static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
                         ];
         } rep;
         struct ip_reply_arg arg;
-#ifdef CONFIG_TCP_MD5SIG
-        struct tcp_md5sig_key *key;
-        struct tcp_md5sig_key tw_key;
-#endif
 
         memset(&rep.th, 0, sizeof(struct tcphdr));
         memset(&arg, 0, sizeof(arg));
@@ -647,23 +649,6 @@ static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
         rep.th.window  = htons(win);
 
 #ifdef CONFIG_TCP_MD5SIG
-        /*
-         * The SKB holds an imcoming packet, but may not have a valid ->sk
-         * pointer. This is especially the case when we're dealing with a
-         * TIME_WAIT ack, because the sk structure is long gone, and only
-         * the tcp_timewait_sock remains. So the md5 key is stashed in that
-         * structure, and we use it in preference.  I believe that (twsk ||
-         * skb->sk) holds true, but we program defensively.
-         */
-        if (!twsk && skb->sk) {
-                key = tcp_v4_md5_do_lookup(skb->sk, ip_hdr(skb)->daddr);
-        } else if (twsk && twsk->tw_md5_keylen) {
-                tw_key.key = twsk->tw_md5_key;
-                tw_key.keylen = twsk->tw_md5_keylen;
-                key = &tw_key;
-        } else
-                key = NULL;
-
         if (key) {
                 int offset = (ts) ? 3 : 0;
 
@@ -685,8 +670,8 @@ static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
                                       ip_hdr(skb)->saddr, /* XXX */
                                       arg.iov[0].iov_len, IPPROTO_TCP, 0);
         arg.csumoffset = offsetof(struct tcphdr, check) / 2;
-        if (twsk)
-                arg.bound_dev_if = twsk->tw_sk.tw_bound_dev_if;
+        if (oif)
+                arg.bound_dev_if = oif;
 
         ip_send_reply(dev_net(skb->dev)->ipv4.tcp_sock, skb,
                       &arg, arg.iov[0].iov_len);
@@ -699,9 +684,12 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
         struct inet_timewait_sock *tw = inet_twsk(sk);
         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 
-        tcp_v4_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
+        tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
-                        tcptw->tw_ts_recent);
+                        tcptw->tw_ts_recent,
+                        tw->tw_bound_dev_if,
+                        tcp_twsk_md5_key(tcptw)
+                        );
 
         inet_twsk_put(tw);
 }
@@ -709,9 +697,11 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
 static void tcp_v4_reqsk_send_ack(struct sk_buff *skb,
                                   struct request_sock *req)
 {
-        tcp_v4_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1,
+        tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
                         tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
-                        req->ts_recent);
+                        req->ts_recent,
+                        0,
+                        tcp_v4_md5_do_lookup(skb->sk, ip_hdr(skb)->daddr));
 }
 
 /*
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 0ae0311082fb..ecdbb9f46541 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -82,6 +82,12 @@ static struct inet_connection_sock_af_ops ipv6_specific;
 #ifdef CONFIG_TCP_MD5SIG
 static struct tcp_sock_af_ops tcp_sock_ipv6_specific;
 static struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
+#else
+static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
+                                                   struct in6_addr *addr)
+{
+        return NULL;
+}
 #endif
 
 static void tcp_v6_hash(struct sock *sk)
@@ -1011,8 +1017,8 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
         kfree_skb(buff);
 }
 
-static void tcp_v6_send_ack(struct tcp_timewait_sock *tw,
-                            struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts)
+static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
+                            struct tcp_md5sig_key *key)
 {
         struct tcphdr *th = tcp_hdr(skb), *t1;
         struct sk_buff *buff;
@@ -1021,22 +1027,6 @@ static void tcp_v6_send_ack(struct tcp_timewait_sock *tw,
         struct sock *ctl_sk = net->ipv6.tcp_sk;
         unsigned int tot_len = sizeof(struct tcphdr);
         __be32 *topt;
-#ifdef CONFIG_TCP_MD5SIG
-        struct tcp_md5sig_key *key;
-        struct tcp_md5sig_key tw_key;
-#endif
-
-#ifdef CONFIG_TCP_MD5SIG
-        if (!tw && skb->sk) {
-                key = tcp_v6_md5_do_lookup(skb->sk, &ipv6_hdr(skb)->daddr);
-        } else if (tw && tw->tw_md5_keylen) {
-                tw_key.key = tw->tw_md5_key;
-                tw_key.keylen = tw->tw_md5_keylen;
-                key = &tw_key;
-        } else {
-                key = NULL;
-        }
-#endif
 
         if (ts)
                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
@@ -1116,16 +1106,17 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
         struct inet_timewait_sock *tw = inet_twsk(sk);
         struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
 
-        tcp_v6_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
+        tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
-                        tcptw->tw_ts_recent);
+                        tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw));
 
         inet_twsk_put(tw);
 }
 
 static void tcp_v6_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req)
 {
-        tcp_v6_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent);
+        tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
+                        tcp_v6_md5_do_lookup(skb->sk, &ipv6_hdr(skb)->daddr));
 }