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 03/11] udp: Always use sendto() rather than send() for forwarding spliced packets
Date: Tue, 22 Nov 2022 14:43:54 +1100 [thread overview]
Message-ID: <20221122034402.1517544-4-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20221122034402.1517544-1-david@gibson.dropbear.id.au>
udp_sock_handler_splice() has two different ways of sending out packets
once it has determined the correct destination socket. For the originating
sockets (which are not connected) it uses sendto() to specify a specific
address. For the forward socket (which is connected) we use send().
However we know the correct destination address even for the forward socket
we do also know the correct destination address. We can use this to use
sendto() instead of send(), removing the need for two different paths and
some staging data structures.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
udp.c | 40 +++++++---------------------------------
1 file changed, 7 insertions(+), 33 deletions(-)
diff --git a/udp.c b/udp.c
index 4caf73e..1e78da5 100644
--- a/udp.c
+++ b/udp.c
@@ -48,7 +48,8 @@
* - forward direction: 127.0.0.1:5000 -> 127.0.0.1:80 in init from bound
* socket s, with epoll reference: index = 80, splice = UDP_TO_NS
* - if udp_splice_to_ns[V4][5000].target_sock:
- * - send packet to udp_splice_to_ns[V4][5000].target_sock
+ * - send packet to udp_splice_to_ns[V4][5000].target_sock, with
+ * destination port 80
* - otherwise:
* - create new socket udp_splice_to_ns[V4][5000].target_sock
* - bind in namespace to 127.0.0.1:5000
@@ -71,7 +72,8 @@
* - forward direction: 127.0.0.1:2000 -> 127.0.0.1:22 in namespace from bound
* socket s, with epoll reference: index = 22, splice = UDP_TO_INIT
* - if udp4_splice_to_init[V4][2000].target_sock:
- * - send packet to udp_splice_to_init[V4][2000].target_sock
+ * - send packet to udp_splice_to_init[V4][2000].target_sock, with
+ * destination port 22
* - otherwise:
* - create new socket udp_splice_to_init[V4][2000].target_sock
* - bind in init to 127.0.0.1:2000
@@ -244,9 +246,6 @@ static struct mmsghdr udp6_l2_mh_tap [UDP_TAP_FRAMES_MEM];
static struct iovec udp_iov_recv [UDP_SPLICE_FRAMES];
static struct mmsghdr udp_mmh_recv [UDP_SPLICE_FRAMES];
-static struct iovec udp_iov_send [UDP_SPLICE_FRAMES];
-static struct mmsghdr udp_mmh_send [UDP_SPLICE_FRAMES];
-
static struct iovec udp_iov_sendto [UDP_SPLICE_FRAMES];
static struct mmsghdr udp_mmh_sendto [UDP_SPLICE_FRAMES];
@@ -530,7 +529,7 @@ static int udp_splice_connect_ns(void *arg)
static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
uint32_t events, const struct timespec *now)
{
- in_port_t src, dst = ref.r.p.udp.udp.port, send_dst = 0;
+ in_port_t src, dst = ref.r.p.udp.udp.port;
struct msghdr *mh = &udp_mmh_recv[0].msg_hdr;
struct sockaddr_storage *sa_s = mh->msg_name;
int s, v6 = ref.r.p.udp.udp.v6, n, i;
@@ -571,8 +570,6 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
case UDP_BACK_TO_INIT:
if (!(s = udp_splice_to_ns[v6][dst].orig_sock))
return;
-
- send_dst = dst;
break;
case UDP_TO_INIT:
src += c->udp.fwd_in.rdelta[src];
@@ -588,25 +585,11 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
case UDP_BACK_TO_NS:
if (!(s = udp_splice_to_init[v6][dst].orig_sock))
return;
-
- send_dst = dst;
break;
default:
return;
}
- if (ref.r.p.udp.udp.splice == UDP_TO_NS ||
- ref.r.p.udp.udp.splice == UDP_TO_INIT) {
- for (i = 0; i < n; i++) {
- struct msghdr *mh_s = &udp_mmh_send[i].msg_hdr;
-
- mh_s->msg_iov->iov_len = udp_mmh_recv[i].msg_len;
- }
-
- sendmmsg(s, udp_mmh_send, n, MSG_NOSIGNAL);
- return;
- }
-
for (i = 0; i < n; i++) {
struct msghdr *mh_s = &udp_mmh_sendto[i].msg_hdr;
@@ -618,7 +601,7 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
((struct sockaddr_in6) {
.sin6_family = AF_INET6,
.sin6_addr = IN6ADDR_LOOPBACK_INIT,
- .sin6_port = htons(send_dst),
+ .sin6_port = htons(dst),
.sin6_scope_id = 0,
});
} else {
@@ -626,7 +609,7 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
((struct sockaddr_in) {
.sin_family = AF_INET,
.sin_addr = { .s_addr = htonl(INADDR_LOOPBACK) },
- .sin_port = htons(send_dst),
+ .sin_port = htons(dst),
.sin_zero = { 0 },
});
}
@@ -1229,15 +1212,6 @@ static void udp_splice_iov_init(void)
iov->iov_len = sizeof(udp_splice_buf[i]);
}
- for (i = 0, h = udp_mmh_send; i < UDP_SPLICE_FRAMES; i++, h++) {
- struct msghdr *mh = &h->msg_hdr;
-
- mh->msg_iov = &udp_iov_send[i];
- mh->msg_iovlen = 1;
- }
- for (i = 0, iov = udp_iov_send; i < UDP_SPLICE_FRAMES; i++, iov++)
- iov->iov_base = udp_splice_buf[i];
-
for (i = 0, h = udp_mmh_sendto; i < UDP_SPLICE_FRAMES; i++, h++) {
struct msghdr *mh = &h->msg_hdr;
--
@@ -48,7 +48,8 @@
* - forward direction: 127.0.0.1:5000 -> 127.0.0.1:80 in init from bound
* socket s, with epoll reference: index = 80, splice = UDP_TO_NS
* - if udp_splice_to_ns[V4][5000].target_sock:
- * - send packet to udp_splice_to_ns[V4][5000].target_sock
+ * - send packet to udp_splice_to_ns[V4][5000].target_sock, with
+ * destination port 80
* - otherwise:
* - create new socket udp_splice_to_ns[V4][5000].target_sock
* - bind in namespace to 127.0.0.1:5000
@@ -71,7 +72,8 @@
* - forward direction: 127.0.0.1:2000 -> 127.0.0.1:22 in namespace from bound
* socket s, with epoll reference: index = 22, splice = UDP_TO_INIT
* - if udp4_splice_to_init[V4][2000].target_sock:
- * - send packet to udp_splice_to_init[V4][2000].target_sock
+ * - send packet to udp_splice_to_init[V4][2000].target_sock, with
+ * destination port 22
* - otherwise:
* - create new socket udp_splice_to_init[V4][2000].target_sock
* - bind in init to 127.0.0.1:2000
@@ -244,9 +246,6 @@ static struct mmsghdr udp6_l2_mh_tap [UDP_TAP_FRAMES_MEM];
static struct iovec udp_iov_recv [UDP_SPLICE_FRAMES];
static struct mmsghdr udp_mmh_recv [UDP_SPLICE_FRAMES];
-static struct iovec udp_iov_send [UDP_SPLICE_FRAMES];
-static struct mmsghdr udp_mmh_send [UDP_SPLICE_FRAMES];
-
static struct iovec udp_iov_sendto [UDP_SPLICE_FRAMES];
static struct mmsghdr udp_mmh_sendto [UDP_SPLICE_FRAMES];
@@ -530,7 +529,7 @@ static int udp_splice_connect_ns(void *arg)
static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
uint32_t events, const struct timespec *now)
{
- in_port_t src, dst = ref.r.p.udp.udp.port, send_dst = 0;
+ in_port_t src, dst = ref.r.p.udp.udp.port;
struct msghdr *mh = &udp_mmh_recv[0].msg_hdr;
struct sockaddr_storage *sa_s = mh->msg_name;
int s, v6 = ref.r.p.udp.udp.v6, n, i;
@@ -571,8 +570,6 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
case UDP_BACK_TO_INIT:
if (!(s = udp_splice_to_ns[v6][dst].orig_sock))
return;
-
- send_dst = dst;
break;
case UDP_TO_INIT:
src += c->udp.fwd_in.rdelta[src];
@@ -588,25 +585,11 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
case UDP_BACK_TO_NS:
if (!(s = udp_splice_to_init[v6][dst].orig_sock))
return;
-
- send_dst = dst;
break;
default:
return;
}
- if (ref.r.p.udp.udp.splice == UDP_TO_NS ||
- ref.r.p.udp.udp.splice == UDP_TO_INIT) {
- for (i = 0; i < n; i++) {
- struct msghdr *mh_s = &udp_mmh_send[i].msg_hdr;
-
- mh_s->msg_iov->iov_len = udp_mmh_recv[i].msg_len;
- }
-
- sendmmsg(s, udp_mmh_send, n, MSG_NOSIGNAL);
- return;
- }
-
for (i = 0; i < n; i++) {
struct msghdr *mh_s = &udp_mmh_sendto[i].msg_hdr;
@@ -618,7 +601,7 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
((struct sockaddr_in6) {
.sin6_family = AF_INET6,
.sin6_addr = IN6ADDR_LOOPBACK_INIT,
- .sin6_port = htons(send_dst),
+ .sin6_port = htons(dst),
.sin6_scope_id = 0,
});
} else {
@@ -626,7 +609,7 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
((struct sockaddr_in) {
.sin_family = AF_INET,
.sin_addr = { .s_addr = htonl(INADDR_LOOPBACK) },
- .sin_port = htons(send_dst),
+ .sin_port = htons(dst),
.sin_zero = { 0 },
});
}
@@ -1229,15 +1212,6 @@ static void udp_splice_iov_init(void)
iov->iov_len = sizeof(udp_splice_buf[i]);
}
- for (i = 0, h = udp_mmh_send; i < UDP_SPLICE_FRAMES; i++, h++) {
- struct msghdr *mh = &h->msg_hdr;
-
- mh->msg_iov = &udp_iov_send[i];
- mh->msg_iovlen = 1;
- }
- for (i = 0, iov = udp_iov_send; i < UDP_SPLICE_FRAMES; i++, iov++)
- iov->iov_base = udp_splice_buf[i];
-
for (i = 0, h = udp_mmh_sendto; i < UDP_SPLICE_FRAMES; i++, h++) {
struct msghdr *mh = &h->msg_hdr;
--
2.38.1
next prev parent reply other threads:[~2022-11-22 3:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-22 3:43 [PATCH 00/11] Simplify handling of "spliced" UDP forwarding David Gibson
2022-11-22 3:43 ` [PATCH 01/11] udp: Also bind() connected ports for "splice" forwarding David Gibson
2022-11-22 3:43 ` [PATCH 02/11] udp: Separate tracking of inbound and outbound packet flows David Gibson
2022-11-22 3:43 ` David Gibson [this message]
2022-11-22 3:43 ` [PATCH 04/11] udp: Don't connect "forward" sockets for spliced flows David Gibson
2022-11-22 3:43 ` [PATCH 05/11] udp: Remove the @bound field from union udp_epoll_ref David Gibson
2022-11-22 3:43 ` [PATCH 06/11] udp: Split splice field in udp_epoll_ref into (mostly) independent bits David Gibson
2022-11-22 3:43 ` [PATCH 07/11] udp: Don't create double sockets for -U port David Gibson
2022-11-22 3:43 ` [PATCH 08/11] udp: Re-use fixed bound sockets for packet forwarding when possible David Gibson
2022-11-22 3:44 ` [PATCH 09/11] udp: Don't explicitly track originating socket for spliced "connections" David Gibson
2022-11-22 3:44 ` [PATCH 10/11] udp: Update UDP "connection" timestamps in both directions David Gibson
2022-11-22 3:44 ` [PATCH 11/11] udp: Simplify udp_sock_handler_splice David Gibson
2022-11-22 21:51 ` [PATCH 00/11] Simplify handling of "spliced" UDP forwarding Stefano Brivio
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