int netlink_parse_interface_address(struct nlmsghdr *nh, void *data)
{
struct ifaces_list ** iface_list = ( struct ifaces_list **) data;
struct iface_entry * iff;
struct ifaces_list * iface_list_tmp;
struct iface_entry iface_tmp;
struct ifaddrmsg *iaddr;
struct rtattr *attribute;
uint32_t len;
uint32_t newsize;
unsigned char is_ipv6;
struct iface_address *addr_tmp;
// strictly for debugging
char addr_str[64];
iaddr = NLMSG_DATA(nh);
// stumbled upon an old system with 4 bytes padding between nlmsghdr and ifaddrmsg, try to detect it
if (!likely_ifaddrmsg(iaddr)) {
iaddr = (unsigned char *)iaddr + 4;
dprintf("Adjusted iaddr at +4");
}
len = nh->nlmsg_len - NLMSG_LENGTH(sizeof(*iaddr));
if (iaddr->ifa_family == AF_INET6)
is_ipv6 = 1;
else if (iaddr->ifa_family == AF_INET)
is_ipv6 = 0;
else {
//dprintf("Got iaddr->ifa_family : %d which is unknown (iaddr->ifa_index : %d)", iaddr->ifa_family, iaddr->ifa_index);
return 0;
}
memset(&iface_tmp, 0, sizeof(iface_tmp));
iface_tmp.index = iaddr->ifa_index;
for (attribute = IFA_RTA(iaddr); RTA_OK(attribute, len); attribute = RTA_NEXT(attribute, len))
{
switch(attribute->rta_type)
{
case IFA_ADDRESS:
// Make room for a new address
iface_tmp.addr_count++;
iface_tmp.addr_list = realloc(iface_tmp.addr_list, sizeof(struct iface_address) * iface_tmp.addr_count);
addr_tmp = &iface_tmp.addr_list[iface_tmp.addr_count-1];
if (is_ipv6)
{
addr_tmp->family = AF_INET6;
memcpy(&addr_tmp->ip.addr6, (unsigned char *) RTA_DATA(attribute), sizeof(__u128));
} else {
addr_tmp->family = AF_INET;
addr_tmp->ip.addr = *(__u32 *) RTA_DATA(attribute);
}
address_calculate_netmask(addr_tmp, iaddr->ifa_prefixlen);
inet_ntop(addr_tmp->family, &addr_tmp->ip, addr_str, sizeof(addr_str));
dprintf("Interface: %s", addr_str);
inet_ntop(addr_tmp->family, &addr_tmp->nm, addr_str, sizeof(addr_str));
dprintf("Netmask: %s", addr_str);
break;
case IFA_LABEL:
strncpy(iface_tmp.name, (unsigned char *) RTA_DATA(attribute), IFNAMSIZ);
dprintf("Copied name %s", iface_tmp.name);
break;
default:
break;
}
}
/*
* try to find the iface by index and name
* An IP alias (eth0:0 for instance) will have the same index but not the
* same name/label. There are no aliases when getting IPv6 address, so
* just search using the index.
*/
if (is_ipv6) {
iff = find_iface_by_index(*iface_list, iface_tmp.index);
if (iff == NULL) {
dprintf("Cannot find iface with index %d", iface_tmp.index);
return 0;
}
}
else
iff = find_iface_by_index_and_name(*iface_list, iface_tmp.index, iface_tmp.name);
if (iff == NULL) {
/* Now we're dealing with an IPv4 alias such as eth0:0. With a regular
* interface, the mac address, mtu, flags, etc. would already have been
* initialized when we did the RTM_GETLINK request. Since an alias
* doesn't count as a physical interface, that didn't happen, so copy
* all of the parent interface's info to this one.
*/
dprintf("%s an alias?", iface_tmp.name);
iff = find_iface_by_index(*iface_list, iface_tmp.index);
if (iff == NULL) {
dprintf("Cannot find iface with index %d", iface_tmp.index);
return 0;
}
memcpy(iface_tmp.hwaddr, iff->hwaddr, 6);
iface_tmp.mtu = iff->mtu;
strncpy(iface_tmp.flags, iff->flags, FLAGS_LEN);
// expand the list to accomodate the new one
newsize = sizeof(struct ifaces_list);
newsize += ((*iface_list)->entries + 1) * sizeof(struct iface_entry);
iface_list_tmp = realloc(*iface_list, newsize);
if(iface_list_tmp == NULL) {
return ENOMEM;
}
iff = &(iface_list_tmp->ifaces[iface_list_tmp->entries]);
memset(iff, 0, sizeof(struct iface_entry));
// copy back saved data in new iface_entry
memcpy(iff->hwaddr, iface_tmp.hwaddr, 6);
iff->mtu = iface_tmp.mtu;
iff->index = iface_tmp.index;
strncpy(iff->flags, iface_tmp.flags, FLAGS_LEN);
strncpy(iff->name, iface_tmp.name, IFNAMSIZ);
iface_list_tmp->entries++;
*iface_list = iface_list_tmp;
}
inet_ntop(addr_tmp->family, &addr_tmp->ip, addr_str, sizeof(addr_str));
dprintf("Appending: %s", addr_str);
iface_entry_append_address(iff, &iface_tmp.addr_list[0]);
dprintf("iff->addr_count = %d; iface_tmp.addr_count = %d", iff->addr_count, iface_tmp.addr_count);
return 0;
}
void process(int sock, struct Interface *interfaces, unsigned char *msg, int len, struct sockaddr_in6 *addr,
struct in6_pktinfo *pkt_info, int hoplimit)
{
char if_namebuf[IF_NAMESIZE] = { "" };
char *if_name = if_indextoname(pkt_info->ipi6_ifindex, if_namebuf);
if (!if_name) {
if_name = "unknown interface";
}
dlog(LOG_DEBUG, 4, "%s received a packet", if_name);
char addr_str[INET6_ADDRSTRLEN];
addrtostr(&addr->sin6_addr, addr_str, sizeof(addr_str));
if (!pkt_info) {
flog(LOG_WARNING, "%s received packet with no pkt_info from %s!", if_name, addr_str);
return;
}
/*
* can this happen?
*/
if (len < sizeof(struct icmp6_hdr)) {
flog(LOG_WARNING, "%s received icmpv6 packet with invalid length (%d) from %s", if_name, len, addr_str);
return;
}
struct icmp6_hdr *icmph = (struct icmp6_hdr *)msg;
if (icmph->icmp6_type != ND_ROUTER_SOLICIT && icmph->icmp6_type != ND_ROUTER_ADVERT) {
/*
* We just want to listen to RSs and RAs
*/
flog(LOG_ERR, "%s icmpv6 filter failed", if_name);
return;
}
if (icmph->icmp6_type == ND_ROUTER_ADVERT) {
if (len < sizeof(struct nd_router_advert)) {
flog(LOG_WARNING, "%s received icmpv6 RA packet with invalid length (%d) from %s", if_name, len, addr_str);
return;
}
if (!IN6_IS_ADDR_LINKLOCAL(&addr->sin6_addr)) {
flog(LOG_WARNING, "%s received icmpv6 RA packet with non-linklocal source address from %s", if_name, addr_str);
return;
}
}
if (icmph->icmp6_type == ND_ROUTER_SOLICIT) {
if (len < sizeof(struct nd_router_solicit)) {
flog(LOG_WARNING, "%s received icmpv6 RS packet with invalid length (%d) from %s", if_name, len, addr_str);
return;
}
}
if (icmph->icmp6_code != 0) {
flog(LOG_WARNING, "%s received icmpv6 RS/RA packet with invalid code (%d) from %s", if_name, icmph->icmp6_code,
addr_str);
return;
}
/* get iface by received if_index */
struct Interface *iface = find_iface_by_index(interfaces, pkt_info->ipi6_ifindex);
if (iface == NULL) {
dlog(LOG_WARNING, 4, "%s received icmpv6 RS/RA packet on an unknown interface with index %d", if_name,
pkt_info->ipi6_ifindex);
return;
}
if (!iface->state_info.ready && (0 != setup_iface(sock, iface))) {
flog(LOG_WARNING, "%s received RS or RA on %s but %s is not ready and setup_iface failed", if_name, iface->props.name,
iface->props.name);
return;
}
if (hoplimit != 255) {
flog(LOG_WARNING, "%s received RS or RA with invalid hoplimit %d from %s", if_name, hoplimit, addr_str);
return;
}
if (icmph->icmp6_type == ND_ROUTER_SOLICIT) {
dlog(LOG_DEBUG, 3, "%s received RS from: %s", if_name, addr_str);
process_rs(sock, iface, msg, len, addr);
} else if (icmph->icmp6_type == ND_ROUTER_ADVERT) {
if (0 == memcmp(&addr->sin6_addr, &iface->props.if_addr, sizeof(iface->props.if_addr))) {
dlog(LOG_DEBUG, 3, "%s received RA from: %s (myself)", if_name, addr_str);
} else {
dlog(LOG_DEBUG, 3, "%s received RA from: %s", if_name, addr_str);
}
process_ra(iface, msg, len, addr);
}
}
