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udp: Introduce recvmmsg()/sendmmsg(), zero-copy path from socket

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Packets are received directly onto pre-cooked, static buffers
for IPv4 (with partial checksum pre-calculation) and IPv6 frames,
with pre-filled Ethernet addresses and, partially, IP headers,
and sent out from the same buffers with sendmmsg(), for both
passt and pasta (non-local traffic only) modes.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2021-07-21 12:01:04 +02:00
parent 7fa3e90290
commit 64a0ba3b27
9 changed files with 537 additions and 61 deletions

82
pcap.c
View file

@ -12,10 +12,12 @@
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
@ -90,6 +92,65 @@ void pcap(char *pkt, size_t len)
write(pcap_fd, pkt, len);
}
/**
* pcapm() - Capture multiple frames from message header to pcap file
* @mh: Pointer to sendmsg() message header buffer
*/
void pcapm(struct msghdr *mh)
{
struct pcap_pkthdr h;
struct timeval tv;
unsigned int i;
if (pcap_fd == -1)
return;
gettimeofday(&tv, NULL);
h.tv_sec = tv.tv_sec;
h.tv_usec = tv.tv_usec;
for (i = 0; i < mh->msg_iovlen; i++) {
struct iovec *iov = &mh->msg_iov[i];
h.caplen = h.len = iov->iov_len - 4;
write(pcap_fd, &h, sizeof(h));
write(pcap_fd, (char *)iov->iov_base + 4, iov->iov_len - 4);
}
}
/**
* pcapm() - Capture multiple frames from multiple message headers to pcap file
* @mmh: Pointer to first sendmmsg() header
*/
void pcapmm(struct mmsghdr *mmh, unsigned int vlen)
{
struct pcap_pkthdr h;
struct timeval tv;
unsigned int i, j;
if (pcap_fd == -1)
return;
gettimeofday(&tv, NULL);
h.tv_sec = tv.tv_sec;
h.tv_usec = tv.tv_usec;
for (i = 0; i < vlen; i++) {
struct msghdr *mh = &mmh[i].msg_hdr;
for (j = 0; j < mh->msg_iovlen; j++) {
struct iovec *iov = &mh->msg_iov[j];
h.caplen = h.len = iov->iov_len - 4;
write(pcap_fd, &h, sizeof(h));
write(pcap_fd, (char *)iov->iov_base + 4,
iov->iov_len - 4);
}
}
}
/**
* pcap_init() - Initialise pcap file
* @c: Execution context
@ -129,10 +190,27 @@ void pcap_init(struct ctx *c, int index)
}
#else /* DEBUG */
void pcap(char *pkt, size_t len) {
void pcap(char *pkt, size_t len)
{
(void)pkt;
(void)len;
}
void pcap_init(void) { }
void pcapm(struct msghdr *mh)
{
(void)mh;
}
void pcapmm(struct mmsghdr *mmh, unsigned int vlen)
{
(void)mmh;
(void)vlen;
}
void pcap_init(struct ctx *c, int sock_index)
{
(void)c;
(void)sock_index;
}
#endif