[PATCH net-next 4/7] ipv4: remove get_rttos

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

From: Willem de Bruijn <willemb@google.com>

Initialize the ip cookie tos field when initializing the cookie, in
ipcm_init_sk.

The existing code inverts the standard pattern for initializing cookie
fields. Default is to initialize the field from the sk, then possibly
overwrite that when parsing cmsgs (the unlikely case).

This field inverts that, setting the field to an illegal value and
after cmsg parsing checking whether the value is still illegal and
thus should be overridden.

Be careful to always apply mask INET_DSCP_MASK, as before.

Signed-off-by: Willem de Bruijn <willemb@google.com>
---
 include/net/ip.h       | 11 +++--------
 net/ipv4/ip_sockglue.c |  4 ++--
 net/ipv4/ping.c        |  1 -
 net/ipv4/raw.c         |  1 -
 net/ipv4/udp.c         |  1 -
 5 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/include/net/ip.h b/include/net/ip.h
index 6af16545b3e3..6819704e2642 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -92,7 +92,9 @@ static inline void ipcm_init(struct ipcm_cookie *ipcm)
 static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
 				const struct inet_sock *inet)
 {
-	ipcm_init(ipcm);
+	*ipcm = (struct ipcm_cookie) {
+		.tos = READ_ONCE(inet->tos) & INET_DSCP_MASK,
+	};
 
 	sockcm_init(&ipcm->sockc, &inet->sk);
 
@@ -256,13 +258,6 @@ static inline u8 ip_sendmsg_scope(const struct inet_sock *inet,
 	return RT_SCOPE_UNIVERSE;
 }
 
-static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
-{
-	u8 dsfield = ipc->tos != -1 ? ipc->tos : READ_ONCE(inet->tos);
-
-	return dsfield & INET_DSCP_MASK;
-}
-
 /* datagram.c */
 int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 6d9c5c20b1c4..98b1e4a8b72e 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -314,8 +314,8 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg, struct ipcm_cookie *ipc,
 				return -EINVAL;
 			if (val < 0 || val > 255)
 				return -EINVAL;
-			ipc->tos = val;
-			ipc->sockc.priority = rt_tos2priority(ipc->tos);
+			ipc->sockc.priority = rt_tos2priority(val);
+			ipc->tos = val & INET_DSCP_MASK;
 			break;
 		case IP_PROTOCOL:
 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 619ddc087957..0215885c6df5 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -768,7 +768,6 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		}
 		faddr = ipc.opt->opt.faddr;
 	}
-	tos = get_rttos(&ipc, inet);
 	scope = ip_sendmsg_scope(inet, &ipc, msg);
 
 	if (ipv4_is_multicast(daddr)) {
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 4304a68d1db0..b1f3fe7962bf 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -581,7 +581,6 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 			daddr = ipc.opt->opt.faddr;
 		}
 	}
-	tos = get_rttos(&ipc, inet);
 	scope = ip_sendmsg_scope(inet, &ipc, msg);
 
 	uc_index = READ_ONCE(inet->uc_index);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index c472c9a57cf6..97ded5f0ae6c 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1405,7 +1405,6 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		faddr = ipc.opt->opt.faddr;
 		connected = 0;
 	}
-	tos = get_rttos(&ipc, inet);
 	scope = ip_sendmsg_scope(inet, &ipc, msg);
 	if (scope == RT_SCOPE_LINK)
 		connected = 0;
-- 
2.48.1.502.g6dc24dfdaf-goog