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qrap: Connect to the first available instance of passt, probe via ARP request

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Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2021-05-21 11:14:52 +02:00
parent 19d254bbbb
commit ad4a85c860
3 changed files with 68 additions and 25 deletions
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15
arp.c
View file

@ -26,20 +26,7 @@
#include "dhcp.h"
#include "util.h"
#include "tap.h"
/**
* struct arpmsg - 802.2 ARP IPv4 payload
* @sha: Sender hardware address
* @sip: Sender IP address
* @tha: Target hardware address
* @tip: Target IP address
*/
struct arpmsg {
unsigned char sha[ETH_ALEN];
unsigned char sip[4];
unsigned char tha[ETH_ALEN];
unsigned char tip[4];
} __attribute__((__packed__));
#include "arp.h"
/**
* arp() - Check if this is an ARP message, reply as needed

14
arp.h
View file

@ -1 +1,15 @@
/**
* struct arpmsg - 802.2 ARP IPv4 payload
* @sha: Sender hardware address
* @sip: Sender IP address
* @tha: Target hardware address
* @tip: Target IP address
*/
struct arpmsg {
unsigned char sha[ETH_ALEN];
unsigned char sip[4];
unsigned char tha[ETH_ALEN];
unsigned char tip[4];
} __attribute__((__packed__));
int arp(struct ctx *c, struct ethhdr *eh, size_t len);

56
qrap.c
View file

@ -14,21 +14,22 @@
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>
#include <linux/if_ether.h>
#include <linux/ipv6.h>
#include <linux/limits.h>
#include <linux/un.h>
#include <limits.h>
#include <net/if.h>
#include <fcntl.h>
#include <net/if_arp.h>
#include "passt.h"
#define STRINGIFY(x) #x
#define STR(x) STRINGIFY(x)
#include "util.h"
#include "arp.h"
static char *qemu_names[] = {
"kvm",
@ -101,10 +102,32 @@ int main(int argc, char **argv)
int i, s, qemu_argc = 0, addr_map = 0, has_dev = 0;
struct sockaddr_un addr = {
.sun_family = AF_UNIX,
.sun_path = UNIX_SOCK_PATH,
};
const struct pci_dev *dev = NULL;
long fd;
struct {
uint32_t vnet_len;
struct ethhdr eh;
struct arphdr ah;
struct arpmsg am;
} probe = {
htonl(42),
{
.h_dest = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
.h_source = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
.h_proto = htons(ETH_P_ARP),
},
{ .ar_hrd = htons(ARPHRD_ETHER),
.ar_pro = htons(ETH_P_IP),
.ar_hln = ETH_ALEN,
.ar_pln = 4,
.ar_op = htons(ARPOP_REQUEST),
},
{
.sha = { 0 }, .sip = { 0 }, .tha = { 0 }, .tip = { 0 },
},
};
char probe_r;
if (argc >= 3) {
fd = strtol(argv[1], NULL, 0);
@ -193,13 +216,32 @@ int main(int argc, char **argv)
qemu_argv[qemu_argc] = NULL;
valid_args:
for (i = 1; i < UNIX_SOCK_MAX; i++) {
struct timeval tv = { .tv_sec = 0, .tv_usec = 100 * 1000 };
s = socket(AF_UNIX, SOCK_STREAM, 0);
setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
if (s < 0) {
perror("socket");
exit(EXIT_FAILURE);
}
if (connect(s, (const struct sockaddr *)&addr, sizeof(addr)) < 0) {
snprintf(addr.sun_path, UNIX_PATH_MAX, UNIX_SOCK_PATH, i);
if (!connect(s, (const struct sockaddr *)&addr, sizeof(addr)) &&
send(s, &probe, sizeof(probe), 0) == sizeof(probe) &&
recv(s, &probe_r, 1, MSG_PEEK) > 0) {
tv.tv_usec = 0;
setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
break;
}
perror("send");
close(s);
}
if (i == UNIX_SOCK_MAX) {
perror("connect");
exit(EXIT_FAILURE);
}