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// SPDX-License-Identifier: GPL-2.0
/* Test IPV6_FLOWINFO cmsg on send and recv */
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <asm/byteorder.h>
#include <error.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <linux/in6.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
/* uapi/glibc weirdness may leave this undefined */
#ifndef IPV6_FLOWINFO
#define IPV6_FLOWINFO 11
#endif
#ifndef IPV6_FLOWLABEL_MGR
#define IPV6_FLOWLABEL_MGR 32
#endif
#define FLOWLABEL_WILDCARD ((uint32_t) -1)
static const char cfg_data[] = "a";
static uint32_t cfg_label = 1;
static void do_send(int fd, bool with_flowlabel, uint32_t flowlabel)
{
char control[CMSG_SPACE(sizeof(flowlabel))] = {0};
struct msghdr msg = {0};
struct iovec iov = {0};
int ret;
iov.iov_base = (char *)cfg_data;
iov.iov_len = sizeof(cfg_data);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
if (with_flowlabel) {
struct cmsghdr *cm;
cm = (void *)control;
cm->cmsg_len = CMSG_LEN(sizeof(flowlabel));
cm->cmsg_level = SOL_IPV6;
cm->cmsg_type = IPV6_FLOWINFO;
*(uint32_t *)CMSG_DATA(cm) = htonl(flowlabel);
msg.msg_control = control;
msg.msg_controllen = sizeof(control);
}
ret = sendmsg(fd, &msg, 0);
if (ret == -1)
error(1, errno, "send");
if (with_flowlabel)
fprintf(stderr, "sent with label %u\n", flowlabel);
else
fprintf(stderr, "sent without label\n");
}
static void do_recv(int fd, bool with_flowlabel, uint32_t expect)
{
char control[CMSG_SPACE(sizeof(expect))];
char data[sizeof(cfg_data)];
struct msghdr msg = {0};
struct iovec iov = {0};
struct cmsghdr *cm;
uint32_t flowlabel;
int ret;
iov.iov_base = data;
iov.iov_len = sizeof(data);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
memset(control, 0, sizeof(control));
msg.msg_control = control;
msg.msg_controllen = sizeof(control);
ret = recvmsg(fd, &msg, 0);
if (ret == -1)
error(1, errno, "recv");
if (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))
error(1, 0, "recv: truncated");
if (ret != sizeof(cfg_data))
error(1, 0, "recv: length mismatch");
if (memcmp(data, cfg_data, sizeof(data)))
error(1, 0, "recv: data mismatch");
cm = CMSG_FIRSTHDR(&msg);
if (with_flowlabel) {
if (!cm)
error(1, 0, "recv: missing cmsg");
if (CMSG_NXTHDR(&msg, cm))
error(1, 0, "recv: too many cmsg");
if (cm->cmsg_level != SOL_IPV6 ||
cm->cmsg_type != IPV6_FLOWINFO)
error(1, 0, "recv: unexpected cmsg level or type");
flowlabel = ntohl(*(uint32_t *)CMSG_DATA(cm));
fprintf(stderr, "recv with label %u\n", flowlabel);
if (expect != FLOWLABEL_WILDCARD && expect != flowlabel)
fprintf(stderr, "recv: incorrect flowlabel %u != %u\n",
flowlabel, expect);
} else {
fprintf(stderr, "recv without label\n");
}
}
static bool get_autoflowlabel_enabled(void)
{
int fd, ret;
char val;
fd = open("/proc/sys/net/ipv6/auto_flowlabels", O_RDONLY);
if (fd == -1)
error(1, errno, "open sysctl");
ret = read(fd, &val, 1);
if (ret == -1)
error(1, errno, "read sysctl");
if (ret == 0)
error(1, 0, "read sysctl: 0");
if (close(fd))
error(1, errno, "close sysctl");
return val == '1';
}
static void flowlabel_get(int fd, uint32_t label, uint8_t share, uint16_t flags)
{
struct in6_flowlabel_req req = {
.flr_action = IPV6_FL_A_GET,
.flr_label = htonl(label),
.flr_flags = flags,
.flr_share = share,
};
/* do not pass IPV6_ADDR_ANY or IPV6_ADDR_MAPPED */
req.flr_dst.s6_addr[0] = 0xfd;
req.flr_dst.s6_addr[15] = 0x1;
if (setsockopt(fd, SOL_IPV6, IPV6_FLOWLABEL_MGR, &req, sizeof(req)))
error(1, errno, "setsockopt flowlabel get");
}
static void parse_opts(int argc, char **argv)
{
int c;
while ((c = getopt(argc, argv, "l:")) != -1) {
switch (c) {
case 'l':
cfg_label = strtoul(optarg, NULL, 0);
break;
default:
error(1, 0, "%s: parse error", argv[0]);
}
}
}
int main(int argc, char **argv)
{
struct sockaddr_in6 addr = {
.sin6_family = AF_INET6,
.sin6_port = htons(8000),
.sin6_addr = IN6ADDR_LOOPBACK_INIT,
};
const int one = 1;
int fdt, fdr;
parse_opts(argc, argv);
fdt = socket(PF_INET6, SOCK_DGRAM, 0);
if (fdt == -1)
error(1, errno, "socket t");
fdr = socket(PF_INET6, SOCK_DGRAM, 0);
if (fdr == -1)
error(1, errno, "socket r");
if (connect(fdt, (void *)&addr, sizeof(addr)))
error(1, errno, "connect");
if (bind(fdr, (void *)&addr, sizeof(addr)))
error(1, errno, "bind");
flowlabel_get(fdt, cfg_label, IPV6_FL_S_EXCL, IPV6_FL_F_CREATE);
if (setsockopt(fdr, SOL_IPV6, IPV6_FLOWINFO, &one, sizeof(one)))
error(1, errno, "setsockopt flowinfo");
if (get_autoflowlabel_enabled()) {
fprintf(stderr, "send no label: recv auto flowlabel\n");
do_send(fdt, false, 0);
do_recv(fdr, true, FLOWLABEL_WILDCARD);
} else {
fprintf(stderr, "send no label: recv no label (auto off)\n");
do_send(fdt, false, 0);
do_recv(fdr, false, 0);
}
fprintf(stderr, "send label\n");
do_send(fdt, true, cfg_label);
do_recv(fdr, true, cfg_label);
if (close(fdr))
error(1, errno, "close r");
if (close(fdt))
error(1, errno, "close t");
return 0;
}
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