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passt: Introduce packet batching mechanism

Browse source 
Receive packets in batches from AF_UNIX, check if they can be sent
with a single syscall, and batch them up with sendmmsg() in case.

A bit rudimentary, currently only implemented for UDP, but it seems
to work.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2021-04-22 13:39:36 +02:00
parent 5b0c88d4ef
commit 1f7cf04d34
8 changed files with 337 additions and 122 deletions

71
udp.c
View file

@ -23,6 +23,7 @@
*
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <errno.h>
#include <limits.h>
@ -35,6 +36,7 @@
#include <sys/epoll.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <unistd.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
@ -105,43 +107,72 @@ void udp_sock_handler(struct ctx *c, int s, uint32_t events)
* udp_tap_handler() - Handle packets from tap
* @c: Execution context
* @af: Address family, AF_INET or AF_INET6
* @in: Input buffer
* @len: Length, including UDP header
* @msg: Input messages
* @count: Message count
*
* Return: count of consumed packets
*/
void udp_tap_handler(struct ctx *c, int af, void *addr, char *in, size_t len)
int udp_tap_handler(struct ctx *c, int af, void *addr,
struct tap_msg *msg, int count)
{
struct udphdr *uh = (struct udphdr *)in;
int s;
/* The caller already checks that all the messages have the same source
* and destination, so we can just take those from the first message.
*/
struct udphdr *uh = (struct udphdr *)msg[0].l4h;
struct mmsghdr mm[UIO_MAXIOV] = { 0 };
struct iovec m[UIO_MAXIOV];
struct sockaddr_in6 s_in6;
struct sockaddr_in s_in;
struct sockaddr *sa;
socklen_t sl;
int i, s;
(void)c;
if (af == AF_INET) {
struct sockaddr_in sa = {
s_in = (struct sockaddr_in) {
.sin_family = AF_INET,
.sin_port = uh->dest,
.sin_addr = *(struct in_addr *)addr,
};
if (!(s = udp4_sock_port[ntohs(uh->source)]))
return;
sa.sin_addr = *(struct in_addr *)addr;
sendto(s, in + sizeof(*uh), len - sizeof(*uh), MSG_DONTWAIT,
(struct sockaddr *)&sa, sizeof(sa));
sa = (struct sockaddr *)&s_in;
sl = sizeof(s_in);
} else if (af == AF_INET6) {
struct sockaddr_in6 sa = {
s_in6 = (struct sockaddr_in6) {
.sin6_family = AF_INET6,
.sin6_port = uh->dest,
.sin6_addr = *(struct in6_addr *)addr,
};
if (!(s = udp6_sock_port[ntohs(uh->source)]))
return;
sendto(s, in + sizeof(*uh), len - sizeof(*uh),
MSG_DONTWAIT | MSG_NOSIGNAL,
(struct sockaddr *)&sa, sizeof(sa));
sa = (struct sockaddr *)&s_in6;
sl = sizeof(s_in6);
} else {
return count;
}
for (i = 0; i < count; i++) {
m[i].iov_base = (char *)((struct udphdr *)msg[i].l4h + 1);
m[i].iov_len = msg[i].l4_len - sizeof(*uh);
mm[i].msg_hdr.msg_name = sa;
mm[i].msg_hdr.msg_namelen = sl;
mm[i].msg_hdr.msg_iov = m + i;
mm[i].msg_hdr.msg_iovlen = 1;
}
if (af == AF_INET) {
if (!(s = udp4_sock_port[ntohs(uh->source)]))
return count;
} else if (af == AF_INET6) {
if (!(s = udp6_sock_port[ntohs(uh->source)]))
return count;
} else {
return count;
}
return sendmmsg(s, mm, count, MSG_DONTWAIT | MSG_NOSIGNAL);
}
/**