Below is my code to loop through the ireq structures. The iterface names
seem to get printed fine but something it wrong with the address stuff.
Later on, when I setup my BPF and read() it blocks forever (even if
packets are coming in).

for (ptr = buf; ptr < buf + ifc.ifc_len; ) {
ifr = (struct ifreq *) ptr;

if (ifr->ifr_addr.sa_len > sizeof(struct sockaddr))
len = ifr->ifr_addr.sa_len;
else
len = sizeof(struct sockaddr);

printf("len: %d\n", len);
ptr += sizeof(ifr->ifr_name) + len;

printf("interface: %s\n", ifr->ifr_name);

if (ifr->ifr_addr.sa_family == AF_LINK) {
struct sockaddr_dl *sdl = (struct sockaddr_dl *) &ifr->ifr_addr;
haddr = sdl->sdl_data + sdl->sdl_nlen;

sa = calloc(1, sizeof(struct sockaddr));
if (sdl->sdl_alen)
memcpy(sa, haddr, sdl->sdl_alen);

switch(sa->sa_family) {
case AF_INET:
sin = (struct sockaddr_in *) haddr;
printf("\taddress: %s\n", inet_ntoa(sin->sin_addr));
break;
case AF_INET6:
sin6 = (struct sockaddr_in6 *) haddr;
printf("\taddress: %s\n", inet_ntop(AF_INET6, &sin6->sin6_addr,
ipstr, sizeof(ipstr)));
break;
}

}

ifrcopy = *ifr;
if (ioctl(sockfd, SIOCGIFFLAGS, &ifrcopy) < 0)
errSys("ioctl error while getting interface flags");

if ((ifrcopy.ifr_flags & IFF_UP) && ((ifrcopy.ifr_flags &
IFF_LOOPBACK) == 0)) {
strncpy(ifname, ifr->ifr_name, IFNAMELEN);
break;
}
}


Output:

Aurora:/Users/chris/dev/network/packetsniffer root# ./psinterface: lo0
interface: lo0
interface: lo0
interface: lo0
interface: gif0
interface: stf0
interface: en0
listening on en0

[ Post a follow-up to this message ]

heheh hey there netBSD :D  the problem is you can't use inet_ntoa() to print
 out hardware addresses.  in your AF_LINK block of code, the addresses provi
ded to you are 6 byte MAC addresses. they are NOT ip addresses. they need to
 be printed byte by byte,or
by using the ether_ntoa() function.  look at the stevens code in the ioctl d
irectory that scorpions gave u a link to. it's in my post.

On Thu, 24 Jun 2004 17:58:28 GMT
chris <chris@misery.net> wrote:

> Below is my code to loop through the ireq structures. The iterface names
> seem to get printed fine but something it wrong with the address stuff.
> Later on, when I setup my BPF and read() it blocks forever (even if
> packets are coming in).
>
> 	for (ptr = buf; ptr < buf + ifc.ifc_len; ) {
> 		ifr = (struct ifreq *) ptr;
>
> 		if (ifr->ifr_addr.sa_len > sizeof(struct sockaddr))
> 			len = ifr->ifr_addr.sa_len;
> 		else
> 			len = sizeof(struct sockaddr);
>
> 		printf("len: %d\n", len);
> 		ptr += sizeof(ifr->ifr_name) + len;
>
> 		printf("interface: %s\n", ifr->ifr_name);
>
> 		if (ifr->ifr_addr.sa_family == AF_LINK) {
> 			struct sockaddr_dl *sdl = (struct sockaddr_dl *) &ifr->ifr_addr;
> 			haddr = sdl->sdl_data + sdl->sdl_nlen;
>
> 			sa = calloc(1, sizeof(struct sockaddr));
> 			if (sdl->sdl_alen)
> 				memcpy(sa, haddr, sdl->sdl_alen);
>
> 			switch(sa->sa_family) {
> 				case AF_INET:
> 					sin = (struct sockaddr_in *) haddr;
> 					printf("\taddress: %s\n", inet_ntoa(sin->sin_addr));
> 			       		break;
> 				case AF_INET6:
> 					sin6 = (struct sockaddr_in6 *) haddr;
> 					printf("\taddress: %s\n", inet_ntop(AF_INET6, &sin6->sin6_addr,
> ipstr, sizeof(ipstr)));
> 					break;
> 			}
>
> 		}
>
> 		ifrcopy = *ifr;
> 		if (ioctl(sockfd, SIOCGIFFLAGS, &ifrcopy) < 0)
> 			errSys("ioctl error while getting interface flags");
>
> 		if ((ifrcopy.ifr_flags & IFF_UP) && ((ifrcopy.ifr_flags &
> IFF_LOOPBACK) == 0)) {
> 			strncpy(ifname, ifr->ifr_name, IFNAMELEN);
> 			break;
> 		}
> 	}
>
>
> Output:
>
> Aurora:/Users/chris/dev/network/packetsniffer root# ./psinterface: lo0
> interface: lo0
> interface: lo0
> interface: lo0
> interface: gif0
> interface: stf0
> interface: en0
> listening on en0
>


--
-sean

[ Post a follow-up to this message ]

sean larsson wrote:

> heheh hey there netBSD :D  the problem is you can't use inet_ntoa() to print out h
ardware addresses.  in your AF_LINK block of code, the addresses provided to you are
 6 byte MAC addresses. they are NOT ip addresses. they need to be printed byte by by
te,
or by using the ether_ntoa() function.  look at the stevens code in the ioctl directory that
 scorpions gave u a link to. it's in my post.
>
> On Thu, 24 Jun 2004 17:58:28 GMT
> chris <chris@misery.net> wrote:
>
> 
>
>
>

Yes thanks, I noticed I was mixing up the AF_LINK stuff with ifr->addr;
check my post on devshed 

[ Post a follow-up to this message ]

chris wrote:
> Below is my code to loop through the ireq structures. The iterface names
> seem to get printed fine but something it wrong with the address stuff.
> Later on, when I setup my BPF and read() it blocks forever (even if
> packets are coming in).
>
>     for (ptr = buf; ptr < buf + ifc.ifc_len; ) {
>         ifr = (struct ifreq *) ptr;
>
>         if (ifr->ifr_addr.sa_len > sizeof(struct sockaddr))
>             len = ifr->ifr_addr.sa_len;
>         else
>             len = sizeof(struct sockaddr);
>
>         printf("len: %d\n", len);
>         ptr += sizeof(ifr->ifr_name) + len;
>
>         printf("interface: %s\n", ifr->ifr_name);
>
>         if (ifr->ifr_addr.sa_family == AF_LINK) {

The line above says that you will only print if the sa_family is
AF_LINK, which neatly excludes either of your switch cases below.

--

Fletcher Glenn

>             struct sockaddr_dl *sdl = (struct sockaddr_dl *)
> &ifr->ifr_addr;
>             haddr = sdl->sdl_data + sdl->sdl_nlen;
>
>             sa = calloc(1, sizeof(struct sockaddr));
>             if (sdl->sdl_alen)
>                 memcpy(sa, haddr, sdl->sdl_alen);
>
>             switch(sa->sa_family) {
>                 case AF_INET:
>                     sin = (struct sockaddr_in *) haddr;
>                     printf("\taddress: %s\n", inet_ntoa(sin->sin_addr));
>                            break;
>                 case AF_INET6:
>                     sin6 = (struct sockaddr_in6 *) haddr;
>                     printf("\taddress: %s\n", inet_ntop(AF_INET6,
> &sin6->sin6_addr, ipstr, sizeof(ipstr)));
>                     break;
>             }
>
>         }
>
>         ifrcopy = *ifr;
>         if (ioctl(sockfd, SIOCGIFFLAGS, &ifrcopy) < 0)
>             errSys("ioctl error while getting interface flags");
>
>         if ((ifrcopy.ifr_flags & IFF_UP) && ((ifrcopy.ifr_flags &
> IFF_LOOPBACK) == 0)) {
>             strncpy(ifname, ifr->ifr_name, IFNAMELEN);
>             break;
>         }
>     }
>
>
> Output:
>
> Aurora:/Users/chris/dev/network/packetsniffer root# ./psinterface: lo0
> interface: lo0
> interface: lo0
> interface: lo0
> interface: gif0
> interface: stf0
> interface: en0
> listening on en0
>

[ Post a follow-up to this message ]