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authorStefano Brivio <sbrivio@redhat.com>2021-04-22 13:39:36 +0200
committerStefano Brivio <sbrivio@redhat.com>2021-04-22 13:39:36 +0200
commit1f7cf04d343f185f9e044fdca70a1d0252492aed (patch)
tree77b28cc46e824f9247151ca21849e74da1cc0d57 /udp.c
parent5b0c88d4ef48c2c3c434929faf418f46db06d555 (diff)
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passt: Introduce packet batching mechanism
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>
Diffstat (limited to 'udp.c')
-rw-r--r--udp.c69
1 files changed, 50 insertions, 19 deletions
diff --git a/udp.c b/udp.c
index 4ed0ae6..dda3a68 100644
--- a/udp.c
+++ b/udp.c
@@ -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;
+ 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);
- sendto(s, in + sizeof(*uh), len - sizeof(*uh),
- MSG_DONTWAIT | MSG_NOSIGNAL,
- (struct sockaddr *)&sa, sizeof(sa));
+ 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);
}
/**