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net-timestamp: expand documentation and test
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Documentation:
  expand explanation of timestamp counter

Test:
  new: flag -I requests and prints PKTINFO
  new: flag -x prints payload (possibly truncated)
  fix: remove pretty print that breaks common flag '-l 1'

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Willem de Bruijn authored and David S. Miller committed Dec 9, 2014
1 parent 829ae9d commit cbd3aad
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Showing 2 changed files with 93 additions and 20 deletions.
23 changes: 15 additions & 8 deletions Documentation/networking/timestamping.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -130,19 +130,26 @@ SOF_TIMESTAMPING_OPT_ID:
have multiple concurrent timestamping requests outstanding. Packets
can be reordered in the transmit path, for instance in the packet
scheduler. In that case timestamps will be queued onto the error
queue out of order from the original send() calls. This option
embeds a counter that is incremented at send() time, to order
timestamps within a flow.
queue out of order from the original send() calls. It is not always
possible to uniquely match timestamps to the original send() calls
based on timestamp order or payload inspection alone, then.

This option associates each packet at send() with a unique
identifier and returns that along with the timestamp. The identifier
is derived from a per-socket u32 counter (that wraps). For datagram
sockets, the counter increments with each sent packet. For stream
sockets, it increments with every byte.

The counter starts at zero. It is initialized the first time that
the socket option is enabled. It is reset each time the option is
enabled after having been disabled. Resetting the counter does not
change the identifiers of existing packets in the system.

This option is implemented only for transmit timestamps. There, the
timestamp is always looped along with a struct sock_extended_err.
The option modifies field ee_data to pass an id that is unique
among all possibly concurrently outstanding timestamp requests for
that socket. In practice, it is a monotonically increasing u32
(that wraps).

In datagram sockets, the counter increments on each send call. In
stream sockets, it increments with every byte.
that socket.


SOF_TIMESTAMPING_OPT_CMSG:
Expand Down
90 changes: 78 additions & 12 deletions Documentation/networking/timestamping/txtimestamp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,7 @@
#include <netpacket/packet.h>
#include <poll.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
Expand All @@ -58,13 +59,23 @@
#include <time.h>
#include <unistd.h>

/* ugly hack to work around netinet/in.h and linux/ipv6.h conflicts */
#ifndef in6_pktinfo
struct in6_pktinfo {
struct in6_addr ipi6_addr;
int ipi6_ifindex;
};
#endif

/* command line parameters */
static int cfg_proto = SOCK_STREAM;
static int cfg_ipproto = IPPROTO_TCP;
static int cfg_num_pkts = 4;
static int do_ipv4 = 1;
static int do_ipv6 = 1;
static int cfg_payload_len = 10;
static bool cfg_show_payload;
static bool cfg_do_pktinfo;
static uint16_t dest_port = 9000;

static struct sockaddr_in daddr;
Expand Down Expand Up @@ -131,6 +142,30 @@ static void print_timestamp(struct scm_timestamping *tss, int tstype,
__print_timestamp(tsname, &tss->ts[0], tskey, payload_len);
}

/* TODO: convert to check_and_print payload once API is stable */
static void print_payload(char *data, int len)
{
int i;

if (len > 70)
len = 70;

fprintf(stderr, "payload: ");
for (i = 0; i < len; i++)
fprintf(stderr, "%02hhx ", data[i]);
fprintf(stderr, "\n");
}

static void print_pktinfo(int family, int ifindex, void *saddr, void *daddr)
{
char sa[INET6_ADDRSTRLEN], da[INET6_ADDRSTRLEN];

fprintf(stderr, " pktinfo: ifindex=%u src=%s dst=%s\n",
ifindex,
saddr ? inet_ntop(family, saddr, sa, sizeof(sa)) : "unknown",
daddr ? inet_ntop(family, daddr, da, sizeof(da)) : "unknown");
}

static void __poll(int fd)
{
struct pollfd pollfd;
Expand All @@ -156,10 +191,9 @@ static void __recv_errmsg_cmsg(struct msghdr *msg, int payload_len)
cm->cmsg_type == SCM_TIMESTAMPING) {
tss = (void *) CMSG_DATA(cm);
} else if ((cm->cmsg_level == SOL_IP &&
cm->cmsg_type == IP_RECVERR) ||
(cm->cmsg_level == SOL_IPV6 &&
cm->cmsg_type == IPV6_RECVERR)) {

cm->cmsg_type == IP_RECVERR) ||
(cm->cmsg_level == SOL_IPV6 &&
cm->cmsg_type == IPV6_RECVERR)) {
serr = (void *) CMSG_DATA(cm);
if (serr->ee_errno != ENOMSG ||
serr->ee_origin != SO_EE_ORIGIN_TIMESTAMPING) {
Expand All @@ -168,6 +202,16 @@ static void __recv_errmsg_cmsg(struct msghdr *msg, int payload_len)
serr->ee_origin);
serr = NULL;
}
} else if (cm->cmsg_level == SOL_IP &&
cm->cmsg_type == IP_PKTINFO) {
struct in_pktinfo *info = (void *) CMSG_DATA(cm);
print_pktinfo(AF_INET, info->ipi_ifindex,
&info->ipi_spec_dst, &info->ipi_addr);
} else if (cm->cmsg_level == SOL_IPV6 &&
cm->cmsg_type == IPV6_PKTINFO) {
struct in6_pktinfo *info6 = (void *) CMSG_DATA(cm);
print_pktinfo(AF_INET6, info6->ipi6_ifindex,
NULL, &info6->ipi6_addr);
} else
fprintf(stderr, "unknown cmsg %d,%d\n",
cm->cmsg_level, cm->cmsg_type);
Expand Down Expand Up @@ -206,7 +250,11 @@ static int recv_errmsg(int fd)
if (ret == -1 && errno != EAGAIN)
error(1, errno, "recvmsg");

__recv_errmsg_cmsg(&msg, ret);
if (ret > 0) {
__recv_errmsg_cmsg(&msg, ret);
if (cfg_show_payload)
print_payload(data, cfg_payload_len);
}

free(data);
return ret == -1;
Expand All @@ -215,9 +263,9 @@ static int recv_errmsg(int fd)
static void do_test(int family, unsigned int opt)
{
char *buf;
int fd, i, val, total_len;
int fd, i, val = 1, total_len;

if (family == IPPROTO_IPV6 && cfg_proto != SOCK_STREAM) {
if (family == AF_INET6 && cfg_proto != SOCK_STREAM) {
/* due to lack of checksum generation code */
fprintf(stderr, "test: skipping datagram over IPv6\n");
return;
Expand All @@ -239,7 +287,6 @@ static void do_test(int family, unsigned int opt)
error(1, errno, "socket");

if (cfg_proto == SOCK_STREAM) {
val = 1;
if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
(char*) &val, sizeof(val)))
error(1, 0, "setsockopt no nagle");
Expand All @@ -253,7 +300,20 @@ static void do_test(int family, unsigned int opt)
}
}

if (cfg_do_pktinfo) {
if (family == AF_INET6) {
if (setsockopt(fd, SOL_IPV6, IPV6_RECVPKTINFO,
&val, sizeof(val)))
error(1, errno, "setsockopt pktinfo ipv6");
} else {
if (setsockopt(fd, SOL_IP, IP_PKTINFO,
&val, sizeof(val)))
error(1, errno, "setsockopt pktinfo ipv4");
}
}

opt |= SOF_TIMESTAMPING_SOFTWARE |
SOF_TIMESTAMPING_OPT_CMSG |
SOF_TIMESTAMPING_OPT_ID;
if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMPING,
(char *) &opt, sizeof(opt)))
Expand All @@ -262,8 +322,6 @@ static void do_test(int family, unsigned int opt)
for (i = 0; i < cfg_num_pkts; i++) {
memset(&ts_prev, 0, sizeof(ts_prev));
memset(buf, 'a' + i, total_len);
buf[total_len - 2] = '\n';
buf[total_len - 1] = '\0';

if (cfg_proto == SOCK_RAW) {
struct udphdr *udph;
Expand Down Expand Up @@ -324,11 +382,13 @@ static void __attribute__((noreturn)) usage(const char *filepath)
" -4: only IPv4\n"
" -6: only IPv6\n"
" -h: show this message\n"
" -I: request PKTINFO\n"
" -l N: send N bytes at a time\n"
" -r: use raw\n"
" -R: use raw (IP_HDRINCL)\n"
" -p N: connect to port N\n"
" -u: use udp\n",
" -u: use udp\n"
" -x: show payload (up to 70 bytes)\n",
filepath);
exit(1);
}
Expand All @@ -338,14 +398,17 @@ static void parse_opt(int argc, char **argv)
int proto_count = 0;
char c;

while ((c = getopt(argc, argv, "46hl:p:rRu")) != -1) {
while ((c = getopt(argc, argv, "46hIl:p:rRux")) != -1) {
switch (c) {
case '4':
do_ipv6 = 0;
break;
case '6':
do_ipv4 = 0;
break;
case 'I':
cfg_do_pktinfo = true;
break;
case 'r':
proto_count++;
cfg_proto = SOCK_RAW;
Expand All @@ -367,6 +430,9 @@ static void parse_opt(int argc, char **argv)
case 'p':
dest_port = strtoul(optarg, NULL, 10);
break;
case 'x':
cfg_show_payload = true;
break;
case 'h':
default:
usage(argv[0]);
Expand Down

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