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ipv4: Avoid using RTO_ONLINK with ip_route_connect().

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Now that ip_rt_fix_tos() doesn't reset ->flowi4_scope unconditionally,
we don't have to rely on the RTO_ONLINK bit to properly set the scope
of a flowi4 structure. We can just set ->flowi4_scope explicitly and
avoid using RTO_ONLINK in ->flowi4_tos.

This patch converts callers of ip_route_connect(). Instead of setting
the tos parameter with RT_CONN_FLAGS(sk), as all callers do, we can:

  1- Drop the tos parameter from ip_route_connect(): its value was
     entirely based on sk, which is also passed as parameter.

  2- Set ->flowi4_scope depending on the SOCK_LOCALROUTE socket option
     instead of always initialising it with RT_SCOPE_UNIVERSE (let's
     define ip_sock_rt_scope() for this purpose).

  3- Avoid overloading ->flowi4_tos with RTO_ONLINK: since the scope is
     now properly initialised, we don't need to tell ip_rt_fix_tos() to
     adjust ->flowi4_scope for us. So let's define ip_sock_rt_tos(),
     which is the same as RT_CONN_FLAGS() but without the RTO_ONLINK
     bit overload.

Note:
  In the original ip_route_connect() code, __ip_route_output_key()
  might clear the RTO_ONLINK bit of fl4->flowi4_tos (because of
  ip_rt_fix_tos()). Therefore flowi4_update_output() had to reuse the
  original tos variable. Now that we don't set RTO_ONLINK any more,
  this is not a problem and we can use fl4->flowi4_tos in
  flowi4_update_output().

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Guillaume Nault 2022-04-21 01:21:33 +02:00 committed by David S. Miller
parent 16a2826777
commit 67e1e2f485
5 changed files with 34 additions and 25 deletions
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36
include/net/route.h
View File

@ -43,6 +43,19 @@
#define RT_CONN_FLAGS(sk) (RT_TOS(inet_sk(sk)->tos) | sock_flag(sk, SOCK_LOCALROUTE))
#define RT_CONN_FLAGS_TOS(sk,tos) (RT_TOS(tos) | sock_flag(sk, SOCK_LOCALROUTE))
static inline __u8 ip_sock_rt_scope(const struct sock *sk)
{
if (sock_flag(sk, SOCK_LOCALROUTE))
return RT_SCOPE_LINK;
return RT_SCOPE_UNIVERSE;
}
static inline __u8 ip_sock_rt_tos(const struct sock *sk)
{
return RT_TOS(inet_sk(sk)->tos);
}
struct ip_tunnel_info;
struct fib_nh;
struct fib_info;
@ -289,39 +302,38 @@ static inline char rt_tos2priority(u8 tos)
* ip_route_newports() calls.
*/
static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst, __be32 src,
u32 tos, int oif, u8 protocol,
static inline void ip_route_connect_init(struct flowi4 *fl4, __be32 dst,
__be32 src, int oif, u8 protocol,
__be16 sport, __be16 dport,
struct sock *sk)
const struct sock *sk)
{
__u8 flow_flags = 0;
if (inet_sk(sk)->transparent)
flow_flags |= FLOWI_FLAG_ANYSRC;
flowi4_init_output(fl4, oif, sk->sk_mark, tos, RT_SCOPE_UNIVERSE,
protocol, flow_flags, dst, src, dport, sport,
sk->sk_uid);
flowi4_init_output(fl4, oif, sk->sk_mark, ip_sock_rt_tos(sk),
ip_sock_rt_scope(sk), protocol, flow_flags, dst,
src, dport, sport, sk->sk_uid);
}
static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
__be32 dst, __be32 src, u32 tos,
int oif, u8 protocol,
static inline struct rtable *ip_route_connect(struct flowi4 *fl4, __be32 dst,
__be32 src, int oif, u8 protocol,
__be16 sport, __be16 dport,
struct sock *sk)
{
struct net *net = sock_net(sk);
struct rtable *rt;
ip_route_connect_init(fl4, dst, src, tos, oif, protocol,
sport, dport, sk);
ip_route_connect_init(fl4, dst, src, oif, protocol, sport, dport, sk);
if (!dst || !src) {
rt = __ip_route_output_key(net, fl4);
if (IS_ERR(rt))
return rt;
ip_rt_put(rt);
flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr);
flowi4_update_output(fl4, oif, fl4->flowi4_tos, fl4->daddr,
fl4->saddr);
}
security_sk_classify_flow(sk, flowi4_to_flowi_common(fl4));
return ip_route_output_flow(net, fl4, sk);

5
net/dccp/ipv4.c
View File

@ -76,9 +76,8 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
orig_dport = usin->sin_port;
fl4 = &inet->cork.fl.u.ip4;
rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
IPPROTO_DCCP,
orig_sport, orig_dport, sk);
sk->sk_bound_dev_if, IPPROTO_DCCP, orig_sport,
orig_dport, sk);
if (IS_ERR(rt))
return PTR_ERR(rt);

6
net/ipv4/af_inet.c
View File

@ -1233,9 +1233,9 @@ static int inet_sk_reselect_saddr(struct sock *sk)
/* Query new route. */
fl4 = &inet->cork.fl.u.ip4;
rt = ip_route_connect(fl4, daddr, 0, RT_CONN_FLAGS(sk),
sk->sk_bound_dev_if, sk->sk_protocol,
inet->inet_sport, inet->inet_dport, sk);
rt = ip_route_connect(fl4, daddr, 0, sk->sk_bound_dev_if,
sk->sk_protocol, inet->inet_sport,
inet->inet_dport, sk);
if (IS_ERR(rt))
return PTR_ERR(rt);

7
net/ipv4/datagram.c
View File

@ -44,10 +44,9 @@ int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len
saddr = inet->mc_addr;
}
fl4 = &inet->cork.fl.u.ip4;
rt = ip_route_connect(fl4, usin->sin_addr.s_addr, saddr,
RT_CONN_FLAGS(sk), oif,
sk->sk_protocol,
inet->inet_sport, usin->sin_port, sk);
rt = ip_route_connect(fl4, usin->sin_addr.s_addr, saddr, oif,
sk->sk_protocol, inet->inet_sport,
usin->sin_port, sk);
if (IS_ERR(rt)) {
err = PTR_ERR(rt);
if (err == -ENETUNREACH)

5
net/ipv4/tcp_ipv4.c
View File

@ -229,9 +229,8 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
orig_dport = usin->sin_port;
fl4 = &inet->cork.fl.u.ip4;
rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
IPPROTO_TCP,
orig_sport, orig_dport, sk);
sk->sk_bound_dev_if, IPPROTO_TCP, orig_sport,
orig_dport, sk);
if (IS_ERR(rt)) {
err = PTR_ERR(rt);
if (err == -ENETUNREACH)