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| author | Sowmini Varadhan <sowmini.varadhan@oracle.com> | 2017-06-15 20:28:55 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-06-16 18:45:15 +0200 |
| commit | 10beea7d7408d0b1c9208757f445c5c710239e0e (patch) | |
| tree | 65fc470f7f2ab3c73c3d3bfd46caa3473098e68e /net/rds | |
| parent | rds: tcp: various endian-ness fixes (diff) | |
| download | linux-10beea7d7408d0b1c9208757f445c5c710239e0e.tar.xz linux-10beea7d7408d0b1c9208757f445c5c710239e0e.zip | |
rds: tcp: Set linger when rejecting an incoming conn in rds_tcp_accept_one
Each time we get an incoming SYN to the RDS_TCP_PORT, the TCP
layer accepts the connection and then the rds_tcp_accept_one()
callback is invoked to process the incoming connection.
rds_tcp_accept_one() may reject the incoming syn for a number of
reasons, e.g., commit 1a0e100fb2c9 ("RDS: TCP: Force every connection
to be initiated by numerically smaller IP address"), or because
we are getting spammed by a malicious node that is triggering
a flood of connection attempts to RDS_TCP_PORT. If the incoming
syn is rejected, no data would have been sent on the TCP socket,
and we do not need to be in TIME_WAIT state, so we set linger on
the TCP socket before closing, thereby closing the socket efficiently
with a RST.
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Tested-by: Imanti Mendez <imanti.mendez@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rds')
| -rw-r--r-- | net/rds/tcp_listen.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c index f9c6312be841..df291ac245d6 100644 --- a/net/rds/tcp_listen.c +++ b/net/rds/tcp_listen.c @@ -112,6 +112,17 @@ struct rds_tcp_connection *rds_tcp_accept_one_path(struct rds_connection *conn) return NULL; } +static void rds_tcp_set_linger(struct socket *sock) +{ + struct linger no_linger = { + .l_onoff = 1, + .l_linger = 0, + }; + + kernel_setsockopt(sock, SOL_SOCKET, SO_LINGER, + (char *)&no_linger, sizeof(no_linger)); +} + int rds_tcp_accept_one(struct socket *sock) { struct socket *new_sock = NULL; @@ -183,7 +194,13 @@ int rds_tcp_accept_one(struct socket *sock) ret = 0; goto out; rst_nsk: - /* reset the newly returned accept sock and bail */ + /* reset the newly returned accept sock and bail. + * It is safe to set linger on new_sock because the RDS connection + * has not been brought up on new_sock, so no RDS-level data could + * be pending on it. By setting linger, we achieve the side-effect + * of avoiding TIME_WAIT state on new_sock. + */ + rds_tcp_set_linger(new_sock); kernel_sock_shutdown(new_sock, SHUT_RDWR); ret = 0; out: |