From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v3 16/16] tcp: Don't defer hash table removal
Date: Thu, 30 Nov 2023 13:02:22 +1100 [thread overview]
Message-ID: <20231130020222.4056647-17-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20231130020222.4056647-1-david@gibson.dropbear.id.au>
When a TCP connection is closed, we mark it by setting events to CLOSED,
then some time later we do final cleanups: closing sockets, removing from
the hash table and so forth.
This does mean that when making a hash lookup we need to exclude any
apparent matches that are CLOSED, since they represent a stale connection.
This can happen in practice if one connection closes and a new one with the
same endpoints is started shortly afterward.
Checking for CLOSED is quite specific to TCP however, and won't work when
we extend the hash table to more general flows. So, alter the code to
immediately remove the connection from the hash table when CLOSED, although
we still defer closing sockets and other cleanup.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
tcp.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/tcp.c b/tcp.c
index 74d06bf..17c7cba 100644
--- a/tcp.c
+++ b/tcp.c
@@ -781,6 +781,9 @@ static void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
tcp_timer_ctl(c, conn);
}
+static void tcp_hash_remove(const struct ctx *c,
+ const struct tcp_tap_conn *conn);
+
/**
* conn_event_do() - Set and log connection events, update epoll state
* @c: Execution context
@@ -825,7 +828,9 @@ static void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn,
flow_dbg(conn, "%s",
num == -1 ? "CLOSED" : tcp_event_str[num]);
- if ((event == TAP_FIN_RCVD) && !(conn->events & SOCK_FIN_RCVD))
+ if (event == CLOSED)
+ tcp_hash_remove(c, conn);
+ else if ((event == TAP_FIN_RCVD) && !(conn->events & SOCK_FIN_RCVD))
conn_flag(c, conn, ACTIVE_CLOSE);
else
tcp_epoll_ctl(c, conn);
@@ -1150,7 +1155,7 @@ static int tcp_hash_match(const struct tcp_tap_conn *conn,
const union inany_addr *faddr,
in_port_t eport, in_port_t fport)
{
- if (conn->events != CLOSED && inany_equals(&conn->faddr, faddr) &&
+ if (inany_equals(&conn->faddr, faddr) &&
conn->eport == eport && conn->fport == fport)
return 1;
@@ -1308,7 +1313,6 @@ static void tcp_conn_destroy(struct ctx *c, union flow *flow)
if (conn->timer != -1)
close(conn->timer);
- tcp_hash_remove(c, conn);
flow_table_compact(c, flow);
}
--
@@ -781,6 +781,9 @@ static void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
tcp_timer_ctl(c, conn);
}
+static void tcp_hash_remove(const struct ctx *c,
+ const struct tcp_tap_conn *conn);
+
/**
* conn_event_do() - Set and log connection events, update epoll state
* @c: Execution context
@@ -825,7 +828,9 @@ static void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn,
flow_dbg(conn, "%s",
num == -1 ? "CLOSED" : tcp_event_str[num]);
- if ((event == TAP_FIN_RCVD) && !(conn->events & SOCK_FIN_RCVD))
+ if (event == CLOSED)
+ tcp_hash_remove(c, conn);
+ else if ((event == TAP_FIN_RCVD) && !(conn->events & SOCK_FIN_RCVD))
conn_flag(c, conn, ACTIVE_CLOSE);
else
tcp_epoll_ctl(c, conn);
@@ -1150,7 +1155,7 @@ static int tcp_hash_match(const struct tcp_tap_conn *conn,
const union inany_addr *faddr,
in_port_t eport, in_port_t fport)
{
- if (conn->events != CLOSED && inany_equals(&conn->faddr, faddr) &&
+ if (inany_equals(&conn->faddr, faddr) &&
conn->eport == eport && conn->fport == fport)
return 1;
@@ -1308,7 +1313,6 @@ static void tcp_conn_destroy(struct ctx *c, union flow *flow)
if (conn->timer != -1)
close(conn->timer);
- tcp_hash_remove(c, conn);
flow_table_compact(c, flow);
}
--
2.43.0
next prev parent reply other threads:[~2023-11-30 2:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-30 2:02 [PATCH v3 00/16] Introduce unified flow table, first steps David Gibson
2023-11-30 2:02 ` [PATCH v3 01/16] treewide: Add messages to static_assert() calls David Gibson
2023-11-30 2:02 ` [PATCH v3 02/16] flow, tcp: Generalise connection types David Gibson
2023-11-30 2:02 ` [PATCH v3 03/16] flow, tcp: Move TCP connection table to unified flow table David Gibson
2023-11-30 2:02 ` [PATCH v3 04/16] flow, tcp: Consolidate flow pointer<->index helpers David Gibson
2023-11-30 2:02 ` [PATCH v3 05/16] util: MAX_FROM_BITS() should be unsigned David Gibson
2023-11-30 2:02 ` [PATCH v3 06/16] flow: Make unified version of flow table compaction David Gibson
2023-11-30 2:02 ` [PATCH v3 07/16] flow, tcp: Add logging helpers for connection related messages David Gibson
2023-11-30 2:02 ` [PATCH v3 08/16] flow: Introduce 'sidx' type to represent one side of one flow David Gibson
2023-12-02 4:35 ` Stefano Brivio
2023-11-30 2:02 ` [PATCH v3 09/16] tcp: Remove unneccessary bounds check in tcp_timer_handler() David Gibson
2023-11-30 2:02 ` [PATCH v3 10/16] flow,tcp: Generalise TCP epoll_ref to generic flows David Gibson
2023-11-30 2:02 ` [PATCH v3 11/16] tcp_splice: Use unsigned to represent side David Gibson
2023-11-30 2:02 ` [PATCH v3 12/16] flow,tcp: Use epoll_ref type including flow and side David Gibson
2023-11-30 2:02 ` [PATCH v3 13/16] test: Avoid hitting guestfish command length limits David Gibson
2023-11-30 2:02 ` [PATCH v3 14/16] pif: Add helpers to get the name of a pif David Gibson
2023-11-30 12:45 ` Stefano Brivio
2023-12-01 0:08 ` David Gibson
2023-11-30 2:02 ` [PATCH v3 15/16] tcp: "TCP" hash secret doesn't need to be TCP specific David Gibson
2023-11-30 2:02 ` David Gibson [this message]
2023-11-30 12:45 ` [PATCH v3 16/16] tcp: Don't defer hash table removal Stefano Brivio
2023-12-01 0:07 ` David Gibson
2023-12-02 4:34 ` Stefano Brivio
2023-12-04 0:43 ` David Gibson
2023-12-04 9:54 ` [PATCH v3 00/16] Introduce unified flow table, first steps Stefano Brivio
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