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From: David Gibson <david@gibson.dropbear.id.au>
To: Stefano Brivio <sbrivio@redhat.com>, passt-dev@passt.top
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH v4 08/16] udp: Re-use fixed bound sockets for packet forwarding when possible
Date: Wed, 30 Nov 2022 15:13:08 +1100	[thread overview]
Message-ID: <20221130041316.2539575-9-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20221130041316.2539575-1-david@gibson.dropbear.id.au>

When we look up udp_splice_to_ns[v6][src].target_sock in
udp_sock_handler_splice, all we really require of the socket is that it
be bound to port src in the pasta guest namespace.  Similarly for
udp_splice_to_init but bound in the init namespace.

Usually these sockets are created temporarily by udp_splice_connect() and
cleaned up by udp_timer().  However, depending on the -u and -U options its
possible we have a permanent socket bound to the relevant port created by
udp_sock_init().  If such a socket exists, we could use it instead of
creating a temporary one.  In fact we *must* use it, because we'll fail
trying to bind() a temporary one to the same port.

So allow this, store permanently bound sockets into udp_splice_to_{ns,init}
in udp_sock_init().  These won't get incorrectly removed by the timer
because we don't put a corresponding entry in the udp_act[] structure
which directs the timer what to clean up.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 udp.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/udp.c b/udp.c
index 3fa74a1..4954a7c 100644
--- a/udp.c
+++ b/udp.c
@@ -153,7 +153,7 @@ struct udp_splice_flow {
 /* Port tracking, arrays indexed by packet source port (host order) */
 static struct udp_tap_port	udp_tap_map	[IP_VERSIONS][NUM_PORTS];
 
-/* Spliced "connections" indexed by originating source port (host order) */
+/* Spliced "connections" indexed by bound port of target_sock (host order) */
 static struct udp_splice_flow udp_splice_to_ns  [IP_VERSIONS][NUM_PORTS];
 static struct udp_splice_flow udp_splice_to_init[IP_VERSIONS][NUM_PORTS];
 
@@ -1095,16 +1095,18 @@ void udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 				bind_addr = &(uint32_t){ htonl(INADDR_LOOPBACK) };
 				uref.udp.splice = uref.udp.orig = true;
 
-				sock_l4(c, AF_INET, IPPROTO_UDP, bind_addr, ifname,
-					port, uref.u32);
+				s = sock_l4(c, AF_INET, IPPROTO_UDP, bind_addr,
+					    ifname, port, uref.u32);
+				udp_splice_to_init[V4][port].target_sock = s;
 			}
 		} else {
 			uref.udp.splice = uref.udp.orig = uref.udp.ns = true;
 
 			bind_addr = &(uint32_t){ htonl(INADDR_LOOPBACK) };
 
-			sock_l4(c, AF_INET, IPPROTO_UDP, bind_addr, ifname,
-				port, uref.u32);
+			s = sock_l4(c, AF_INET, IPPROTO_UDP, bind_addr,
+				    ifname, port, uref.u32);
+			udp_splice_to_ns[V4][port].target_sock = s;
 		}
 	}
 
@@ -1127,15 +1129,17 @@ void udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 				bind_addr = &in6addr_loopback;
 				uref.udp.splice = uref.udp.orig = true;
 
-				sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr, ifname,
-					port, uref.u32);
+				s = sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr,
+					    ifname, port, uref.u32);
+				udp_splice_to_init[V6][port].target_sock = s;
 			}
 		} else {
 			bind_addr = &in6addr_loopback;
 			uref.udp.splice = uref.udp.orig = uref.udp.ns = true;
 
-			sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr, ifname,
-				port, uref.u32);
+			s = sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr,
+				    ifname, port, uref.u32);
+			udp_splice_to_ns[V6][port].target_sock = s;
 		}
 	}
 }
-- 
@@ -153,7 +153,7 @@ struct udp_splice_flow {
 /* Port tracking, arrays indexed by packet source port (host order) */
 static struct udp_tap_port	udp_tap_map	[IP_VERSIONS][NUM_PORTS];
 
-/* Spliced "connections" indexed by originating source port (host order) */
+/* Spliced "connections" indexed by bound port of target_sock (host order) */
 static struct udp_splice_flow udp_splice_to_ns  [IP_VERSIONS][NUM_PORTS];
 static struct udp_splice_flow udp_splice_to_init[IP_VERSIONS][NUM_PORTS];
 
@@ -1095,16 +1095,18 @@ void udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 				bind_addr = &(uint32_t){ htonl(INADDR_LOOPBACK) };
 				uref.udp.splice = uref.udp.orig = true;
 
-				sock_l4(c, AF_INET, IPPROTO_UDP, bind_addr, ifname,
-					port, uref.u32);
+				s = sock_l4(c, AF_INET, IPPROTO_UDP, bind_addr,
+					    ifname, port, uref.u32);
+				udp_splice_to_init[V4][port].target_sock = s;
 			}
 		} else {
 			uref.udp.splice = uref.udp.orig = uref.udp.ns = true;
 
 			bind_addr = &(uint32_t){ htonl(INADDR_LOOPBACK) };
 
-			sock_l4(c, AF_INET, IPPROTO_UDP, bind_addr, ifname,
-				port, uref.u32);
+			s = sock_l4(c, AF_INET, IPPROTO_UDP, bind_addr,
+				    ifname, port, uref.u32);
+			udp_splice_to_ns[V4][port].target_sock = s;
 		}
 	}
 
@@ -1127,15 +1129,17 @@ void udp_sock_init(const struct ctx *c, int ns, sa_family_t af,
 				bind_addr = &in6addr_loopback;
 				uref.udp.splice = uref.udp.orig = true;
 
-				sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr, ifname,
-					port, uref.u32);
+				s = sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr,
+					    ifname, port, uref.u32);
+				udp_splice_to_init[V6][port].target_sock = s;
 			}
 		} else {
 			bind_addr = &in6addr_loopback;
 			uref.udp.splice = uref.udp.orig = uref.udp.ns = true;
 
-			sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr, ifname,
-				port, uref.u32);
+			s = sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr,
+				    ifname, port, uref.u32);
+			udp_splice_to_ns[V6][port].target_sock = s;
 		}
 	}
 }
-- 
2.38.1


  parent reply	other threads:[~2022-11-30  4:13 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-30  4:13 [PATCH v4 00/16] Simplify and correct handling of "spliced" UDP forwarding David Gibson
2022-11-30  4:13 ` [PATCH v4 01/16] udp: Also bind() connected ports for "splice" forwarding David Gibson
2022-11-30  4:13 ` [PATCH v4 02/16] udp: Separate tracking of inbound and outbound packet flows David Gibson
2022-11-30  4:13 ` [PATCH v4 03/16] udp: Always use sendto() rather than send() for forwarding spliced packets David Gibson
2022-11-30  4:13 ` [PATCH v4 04/16] udp: Don't connect "forward" sockets for spliced flows David Gibson
2022-11-30  4:13 ` [PATCH v4 05/16] udp: Remove the @bound field from union udp_epoll_ref David Gibson
2022-11-30  4:13 ` [PATCH v4 06/16] udp: Split splice field in udp_epoll_ref into (mostly) independent bits David Gibson
2022-11-30  4:13 ` [PATCH v4 07/16] udp: Don't create double sockets for -U port David Gibson
2022-11-30  4:13 ` David Gibson [this message]
2022-11-30  4:13 ` [PATCH v4 09/16] udp: Don't explicitly track originating socket for spliced "connections" David Gibson
2022-11-30  4:13 ` [PATCH v4 10/16] udp: Update UDP "connection" timestamps in both directions David Gibson
2022-11-30  4:13 ` [PATCH v4 11/16] udp: Simplify udp_sock_handler_splice David Gibson
2022-11-30  4:13 ` [PATCH v4 12/16] udp: Make UDP_SPLICE_FRAMES and UDP_TAP_FRAMES_MEM the same thing David Gibson
2022-11-30  4:13 ` [PATCH v4 13/16] udp: Add helper to extract port from a sockaddr_in or sockaddr_in6 David Gibson
2022-11-30  4:13 ` [PATCH v4 14/16] udp: Unify buffers for tap and splice paths David Gibson
2022-11-30  4:13 ` [PATCH v4 15/16] udp: Split send half of udp_sock_handler_splice() from the receive half David Gibson
2022-11-30  4:13 ` [PATCH v4 16/16] udp: Correct splice forwarding when receiving from multiple sources David Gibson
2022-12-06  6:45 ` [PATCH v4 00/16] Simplify and correct handling of "spliced" UDP forwarding Stefano Brivio

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