kern/99558: FreeBSD 6.1 can't send packets to INADDR_BROADCAST

[Andrey V. Elsukov]

>Number:         99558
>Category:       kern
>Synopsis:       FreeBSD 6.1 can't send packets to INADDR_BROADCAST
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Jun 27 17:10:20 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Andrey V. Elsukov
>Release:        FreeBSD 6.1
>Organization:
>Environment:
	FreeBSD 6.1-PRERELEASE, 6.1-STABLE have this bug
	FreeBSD 4.11-RELEASE, FreeBSD 5.4-STABLE, FreeBSD 5.5-RELEASE works ok.
>Description:
	FreeBSD 6.1 can't send UDP Broadcast. 
	Here is simple test programm:

--- test.c ---
#include <stdio.h>
#include <err.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>

int main(void)
{
	int sock, val, ret;
	struct sockaddr_in addr;

	sock = socket(AF_INET, SOCK_DGRAM, 0);
	if (sock < 0)
		err(1, "socket()");

	addr.sin_family = AF_INET;
	addr.sin_port = htons(5000);
	addr.sin_addr.s_addr = htonl(INADDR_BROADCAST);

	val = 1;
	ret = setsockopt(sock, SOL_SOCKET, SO_BROADCAST,
					(const char*)&val, sizeof(val));
	if (ret < 0)
		err(2, "setsockopt()");

	ret = sendto(sock, "test", 4, 0, (struct sockaddr*)&addr,
				sizeof(addr));

	if (ret != 4)
		err(3, "sendto()");

	close(sock);
	return (0);
}
--- test.c ---


1. I've connect via PPTP tunnel and my host have default route.
[butcher at btr butcher]> ./test
[butcher at btr butcher]> sudo tcpdump -ni ng0 -XX udp port 5000 
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on ng0, link-type NULL (BSD loopback), capture size 96 bytes
19:25:32.169657 IP 192.168.3.6.53565 > 255.255.255.255.5000: UDP, length 4
        0x0000:  0200 0000 4500 0020 241a 0000 4011 9305  ....E...$... at ...
        0x0010:  c0a8 0306 ffff ffff d13d 1388 000c 6f88  .........=....o.
        0x0020:  7465 7374                                test
^C

Message was send, but via PPTP to default destination.

2. I've not connected to PPTP server and don't have default route.

[butcher at btr butcher]> netstat -rnf inet | grep default
[butcher at btr butcher]> ./test
test: sendto(): Network is unreachable

test programm was fail with error.

3. I have the default route.
[butcher at btr butcher]> sudo route add default server
add net default: gateway server
[butcher at btr butcher]> ./test
[butcher at btr butcher]> sudo tcpdump -ni nve0 -XX udp port 5000
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on nve0, link-type EN10MB (Ethernet), capture size 96 bytes
19:29:51.988429 IP 192.168.4.234.54134 > 255.255.255.255.5000: UDP, length 4
0x0000:  0080 4836 9531 4255 5443 4821 0800 4500  ..H6.1BUTCH!..E.
0x0010:  0020 2459 0000 4011 90e2 c0a8 04ea ffff  ..$Y.. at .........
0x0020:  ffff d376 1388 000c 6b6b 7465 7374       ...v....kktest
^C

Message was send to default destination with router's destination MAC address.

>How-To-Repeat:
	Always.
>Fix:
	
>Release-Note:
>Audit-Trail:
>Unformatted: