ipv6: Refactor update of IPv6 flowi destination address for srcrt (RH) option

There are more than a dozen occurrences of following code in the
IPv6 stack:

    if (opt && opt->srcrt) {
            struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
            ipv6_addr_copy(&final, &fl.fl6_dst);
            ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
            final_p = &final;
    }

Replace those with a helper. Note that the helper overrides final_p
in all cases. This is ok as final_p was previously initialized to
NULL when declared.

Signed-off-by: Arnaud Ebalard <arno@natisbad.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

9 files changed, 51 insertions, 96 deletions

diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 09169889959..6e3f32575df 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -248,7 +248,7 @@ static int dccp_v6_send_response(struct sock *sk, struct request_sock *req,
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct sk_buff *skb;
         struct ipv6_txoptions *opt = NULL;
-        struct in6_addr *final_p = NULL, final;
+        struct in6_addr *final_p, final;
         struct flowi fl;
         int err = -1;
         struct dst_entry *dst;
@@ -265,13 +265,7 @@ static int dccp_v6_send_response(struct sock *sk, struct request_sock *req,
 
         opt = np->opt;
 
-        if (opt != NULL && opt->srcrt != NULL) {
-                const struct rt0_hdr *rt0 = (struct rt0_hdr *)opt->srcrt;
-
-                ipv6_addr_copy(&final, &fl.fl6_dst);
-                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                final_p = &final;
-        }
+        final_p = fl6_update_dst(&fl, opt, &final);
 
         err = ip6_dst_lookup(sk, &dst, &fl);
         if (err)
@@ -545,19 +539,13 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
                 goto out_overflow;
 
         if (dst == NULL) {
-                struct in6_addr *final_p = NULL, final;
+                struct in6_addr *final_p, final;
                 struct flowi fl;
 
                 memset(&fl, 0, sizeof(fl));
                 fl.proto = IPPROTO_DCCP;
                 ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
-                if (opt != NULL && opt->srcrt != NULL) {
-                        const struct rt0_hdr *rt0 = (struct rt0_hdr *)opt->srcrt;
-
-                        ipv6_addr_copy(&final, &fl.fl6_dst);
-                        ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                        final_p = &final;
-                }
+                final_p = fl6_update_dst(&fl, opt, &final);
                 ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
                 fl.oif = sk->sk_bound_dev_if;
                 fl.fl_ip_dport = inet_rsk(req)->rmt_port;
@@ -885,7 +873,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
         struct inet_sock *inet = inet_sk(sk);
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct dccp_sock *dp = dccp_sk(sk);
-        struct in6_addr *saddr = NULL, *final_p = NULL, final;
+        struct in6_addr *saddr = NULL, *final_p, final;
         struct flowi fl;
         struct dst_entry *dst;
         int addr_type;
@@ -988,13 +976,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
         fl.fl_ip_sport = inet->inet_sport;
         security_sk_classify_flow(sk, &fl);
 
-        if (np->opt != NULL && np->opt->srcrt != NULL) {
-                const struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
-
-                ipv6_addr_copy(&final, &fl.fl6_dst);
-                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                final_p = &final;
-        }
+        final_p = fl6_update_dst(&fl, np->opt, &final);
 
         err = ip6_dst_lookup(sk, &dst, &fl);
         if (err)
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index e733942dafe..94b1b9c954b 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -651,7 +651,7 @@ int inet6_sk_rebuild_header(struct sock *sk)
 
         if (dst == NULL) {
                 struct inet_sock *inet = inet_sk(sk);
-                struct in6_addr *final_p = NULL, final;
+                struct in6_addr *final_p, final;
                 struct flowi fl;
 
                 memset(&fl, 0, sizeof(fl));
@@ -665,12 +665,7 @@ int inet6_sk_rebuild_header(struct sock *sk)
                 fl.fl_ip_sport = inet->inet_sport;
                 security_sk_classify_flow(sk, &fl);
 
-                if (np->opt && np->opt->srcrt) {
-                        struct rt0_hdr *rt0 = (struct rt0_hdr *) np->opt->srcrt;
-                        ipv6_addr_copy(&final, &fl.fl6_dst);
-                        ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                        final_p = &final;
-                }
+                final_p = fl6_update_dst(&fl, np->opt, &final);
 
                 err = ip6_dst_lookup(sk, &dst, &fl);
                 if (err) {
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 712684687c9..7d929a22cbc 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -38,10 +38,11 @@ int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
         struct inet_sock        *inet = inet_sk(sk);
         struct ipv6_pinfo       *np = inet6_sk(sk);
-        struct in6_addr         *daddr, *final_p = NULL, final;
+        struct in6_addr         *daddr, *final_p, final;
         struct dst_entry        *dst;
         struct flowi            fl;
         struct ip6_flowlabel    *flowlabel = NULL;
+        struct ipv6_txoptions   *opt;
         int                     addr_type;
         int                     err;
 
@@ -155,19 +156,8 @@ ipv4_connected:
 
         security_sk_classify_flow(sk, &fl);
 
-        if (flowlabel) {
-                if (flowlabel->opt && flowlabel->opt->srcrt) {
-                        struct rt0_hdr *rt0 = (struct rt0_hdr *) flowlabel->opt->srcrt;
-                        ipv6_addr_copy(&final, &fl.fl6_dst);
-                        ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                        final_p = &final;
-                }
-        } else if (np->opt && np->opt->srcrt) {
-                struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
-                ipv6_addr_copy(&final, &fl.fl6_dst);
-                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                final_p = &final;
-        }
+        opt = flowlabel ? flowlabel->opt : np->opt;
+        final_p = fl6_update_dst(&fl, opt, &final);
 
         err = ip6_dst_lookup(sk, &dst, &fl);
         if (err)
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 8a659f92d17..853a633a94d 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -874,3 +874,27 @@ struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
         return opt;
 }
 
+/**
+ * fl6_update_dst - update flowi destination address with info given
+ *                  by srcrt option, if any.
+ *
+ * @fl: flowi for which fl6_dst is to be updated
+ * @opt: struct ipv6_txoptions in which to look for srcrt opt
+ * @orig: copy of original fl6_dst address if modified
+ *
+ * Returns NULL if no txoptions or no srcrt, otherwise returns orig
+ * and initial value of fl->fl6_dst set in orig
+ */
+struct in6_addr *fl6_update_dst(struct flowi *fl,
+                                const struct ipv6_txoptions *opt,
+                                struct in6_addr *orig)
+{
+        if (!opt || !opt->srcrt)
+                return NULL;
+
+        ipv6_addr_copy(orig, &fl->fl6_dst);
+        ipv6_addr_copy(&fl->fl6_dst, ((struct rt0_hdr *)opt->srcrt)->addr);
+        return orig;
+}
+
+EXPORT_SYMBOL_GPL(fl6_update_dst);
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index 0c5e3c3b7fd..8a1628023bd 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -185,7 +185,7 @@ int inet6_csk_xmit(struct sk_buff *skb)
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct flowi fl;
         struct dst_entry *dst;
-        struct in6_addr *final_p = NULL, final;
+        struct in6_addr *final_p, final;
 
         memset(&fl, 0, sizeof(fl));
         fl.proto = sk->sk_protocol;
@@ -199,12 +199,7 @@ int inet6_csk_xmit(struct sk_buff *skb)
         fl.fl_ip_dport = inet->inet_dport;
         security_sk_classify_flow(sk, &fl);
 
-        if (np->opt && np->opt->srcrt) {
-                struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
-                ipv6_addr_copy(&final, &fl.fl6_dst);
-                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                final_p = &final;
-        }
+        final_p = fl6_update_dst(&fl, np->opt, &final);
 
         dst = __inet6_csk_dst_check(sk, np->dst_cookie);
 
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 4a4dcbe4f8b..864eb8e03b1 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -725,7 +725,7 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 {
         struct ipv6_txoptions opt_space;
         struct sockaddr_in6 * sin6 = (struct sockaddr_in6 *) msg->msg_name;
-        struct in6_addr *daddr, *final_p = NULL, final;
+        struct in6_addr *daddr, *final_p, final;
         struct inet_sock *inet = inet_sk(sk);
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct raw6_sock *rp = raw6_sk(sk);
@@ -847,13 +847,7 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
         if (ipv6_addr_any(&fl.fl6_src) && !ipv6_addr_any(&np->saddr))
                 ipv6_addr_copy(&fl.fl6_src, &np->saddr);
 
-        /* merge ip6_build_xmit from ip6_output */
-        if (opt && opt->srcrt) {
-                struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
-                ipv6_addr_copy(&final, &fl.fl6_dst);
-                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                final_p = &final;
-        }
+        final_p = fl6_update_dst(&fl, opt, &final);
 
         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst))
                 fl.oif = np->mcast_oif;
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index 34d1f0690d7..12383705dba 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -240,17 +240,12 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
          * me if there is a preferred way.
          */
         {
-                struct in6_addr *final_p = NULL, final;
+                struct in6_addr *final_p, final;
                 struct flowi fl;
                 memset(&fl, 0, sizeof(fl));
                 fl.proto = IPPROTO_TCP;
                 ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
-                if (np->opt && np->opt->srcrt) {
-                        struct rt0_hdr *rt0 = (struct rt0_hdr *) np->opt->srcrt;
-                        ipv6_addr_copy(&final, &fl.fl6_dst);
-                        ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                        final_p = &final;
-                }
+                final_p = fl6_update_dst(&fl, np->opt, &final);
                 ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
                 fl.oif = sk->sk_bound_dev_if;
                 fl.mark = sk->sk_mark;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 2b7c3a100e2..e487080d02d 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -129,7 +129,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
         struct inet_connection_sock *icsk = inet_csk(sk);
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct tcp_sock *tp = tcp_sk(sk);
-        struct in6_addr *saddr = NULL, *final_p = NULL, final;
+        struct in6_addr *saddr = NULL, *final_p, final;
         struct flowi fl;
         struct dst_entry *dst;
         int addr_type;
@@ -250,12 +250,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
         fl.fl_ip_dport = usin->sin6_port;
         fl.fl_ip_sport = inet->inet_sport;
 
-        if (np->opt && np->opt->srcrt) {
-                struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
-                ipv6_addr_copy(&final, &fl.fl6_dst);
-                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                final_p = &final;
-        }
+        final_p = fl6_update_dst(&fl, np->opt, &final);
 
         security_sk_classify_flow(sk, &fl);
 
@@ -477,7 +472,7 @@ static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct sk_buff * skb;
         struct ipv6_txoptions *opt = NULL;
-        struct in6_addr * final_p = NULL, final;
+        struct in6_addr * final_p, final;
         struct flowi fl;
         struct dst_entry *dst;
         int err = -1;
@@ -494,12 +489,7 @@ static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
         security_req_classify_flow(req, &fl);
 
         opt = np->opt;
-        if (opt && opt->srcrt) {
-                struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
-                ipv6_addr_copy(&final, &fl.fl6_dst);
-                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                final_p = &final;
-        }
+        final_p = fl6_update_dst(&fl, opt, &final);
 
         err = ip6_dst_lookup(sk, &dst, &fl);
         if (err)
@@ -1392,18 +1382,13 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
                 goto out_overflow;
 
         if (dst == NULL) {
-                struct in6_addr *final_p = NULL, final;
+                struct in6_addr *final_p, final;
                 struct flowi fl;
 
                 memset(&fl, 0, sizeof(fl));
                 fl.proto = IPPROTO_TCP;
                 ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
-                if (opt && opt->srcrt) {
-                        struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
-                        ipv6_addr_copy(&final, &fl.fl6_dst);
-                        ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                        final_p = &final;
-                }
+                final_p = fl6_update_dst(&fl, opt, &final);
                 ipv6_addr_copy(&fl.fl6_src, &treq->loc_addr);
                 fl.oif = sk->sk_bound_dev_if;
                 fl.mark = sk->sk_mark;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 3048f906c04..4aea57dec75 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -929,7 +929,7 @@ int udpv6_sendmsg(struct kiocb *iocb, struct sock *sk,
         struct inet_sock *inet = inet_sk(sk);
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) msg->msg_name;
-        struct in6_addr *daddr, *final_p = NULL, final;
+        struct in6_addr *daddr, *final_p, final;
         struct ipv6_txoptions *opt = NULL;
         struct ip6_flowlabel *flowlabel = NULL;
         struct flowi fl;
@@ -1099,14 +1099,9 @@ do_udp_sendmsg:
                 ipv6_addr_copy(&fl.fl6_src, &np->saddr);
         fl.fl_ip_sport = inet->inet_sport;
 
-        /* merge ip6_build_xmit from ip6_output */
-        if (opt && opt->srcrt) {
-                struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
-                ipv6_addr_copy(&final, &fl.fl6_dst);
-                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
-                final_p = &final;
+        final_p = fl6_update_dst(&fl, opt, &final);
+        if (final_p)
                 connected = 0;
-        }
 
         if (!fl.oif && ipv6_addr_is_multicast(&fl.fl6_dst)) {
                 fl.oif = np->mcast_oif;