#define ICMP_CODE_TTL_EXCEEDED 0
/* Generic IP checksum routine */
-static inline uint16_t ip_csum(uint8_t *iph,int32_t count)
+static inline uint16_t ip_csum(const uint8_t *iph,int32_t count)
{
register uint32_t sum=0;
* By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
* Arnt Gulbrandsen.
*/
-static inline uint16_t ip_fast_csum(uint8_t *iph, int32_t ihl) {
+static inline uint16_t ip_fast_csum(const uint8_t *iph, int32_t ihl) {
uint32_t sum;
__asm__ __volatile__(
uint8_t tos;
uint16_t tot_len;
uint16_t id;
- uint16_t frag_off;
+ uint16_t frag;
+#define IPHDR_FRAG_OFF ((uint16_t)0x1fff)
+#define IPHDR_FRAG_MORE ((uint16_t)0x2000)
+#define IPHDR_FRAG_DONT ((uint16_t)0x4000)
+/* reserved 0x8000 */
uint8_t ttl;
uint8_t protocol;
uint16_t check;
uint8_t type;
uint8_t code;
uint16_t check;
- union {
+ union icmpinfofield {
uint32_t unused;
struct {
uint8_t pointer;
} echo;
} d;
};
+
+static const union icmpinfofield icmp_noinfo;
static void netlink_packet_deliver(struct netlink *st,
struct netlink_client *client,
h->iph.tos=0;
h->iph.tot_len=htons(len+(h->iph.ihl*4)+8);
h->iph.id=0;
- h->iph.frag_off=0;
+ h->iph.frag=0;
h->iph.ttl=255; /* XXX should be configurable */
h->iph.protocol=1;
h->iph.saddr=htonl(st->secnet_address);
icmph=(struct icmphdr *)buf->start;
if (iph->protocol==1) {
switch(icmph->type) {
- case 3: /* Destination unreachable */
- case 11: /* Time Exceeded */
- case 12: /* Parameter Problem */
+ /* Based on http://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml#icmp-parameters-types
+ * as retrieved Thu, 20 Mar 2014 00:16:44 +0000.
+ * Deprecated, reserved, unassigned and experimental
+ * options are treated as not safe to reply to.
+ */
+ case 0: /* Echo Reply */
+ case 8: /* Echo */
+ case 13: /* Timestamp */
+ case 14: /* Timestamp Reply */
+ return True;
+ default:
return False;
}
}
/* How do we spot broadcast destination addresses? */
- if (ntohs(iph->frag_off)&0x1fff) return False; /* Non-initial fragment */
+ if (ntohs(iph->frag)&IPHDR_FRAG_OFF) return False;
source=ntohl(iph->saddr);
if (source==0) return False;
if ((source&0xff000000)==0x7f000000) return False;
/* client indicates where the packet we're constructing a response to
comes from. NULL indicates the host. */
static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
- struct netlink_client *client,
- uint8_t type, uint8_t code)
+ uint8_t type, uint8_t code,
+ union icmpinfofield info)
{
struct icmphdr *h;
uint16_t len;
struct iphdr *iph=(struct iphdr *)buf->start;
len=netlink_icmp_reply_len(buf);
h=netlink_icmp_tmpl(st,ntohl(iph->saddr),len);
- h->type=type; h->code=code;
+ h->type=type; h->code=code; h->d=info;
memcpy(buf_append(&st->icmp,len),buf->start,len);
netlink_icmp_csum(h);
netlink_packet_deliver(st,NULL,&st->icmp);
client->outcount++;
}
+/* Deliver a packet to the host; used after we have decided that that
+ * is what to do with it. */
+static void netlink_host_deliver(struct netlink *st,
+ uint32_t source, uint32_t dest,
+ struct buffer_if *buf)
+{
+ st->deliver_to_host(st->dst,buf);
+ st->outcount++;
+}
+
/* Deliver a packet. "client" is the _origin_ of the packet, not its
destination, and is NULL for packets from the host and packets
generated internally in secnet. */
/* The packet's not going down a tunnel. It might (ought to)
be for the host. */
if (ipset_contains_addr(st->networks,dest)) {
- st->deliver_to_host(st->dst,buf);
- st->outcount++;
+ netlink_host_deliver(st,source,dest,buf);
BUF_ASSERT_FREE(buf);
} else {
string_t s,d;
Message(M_DEBUG,"%s: don't know where to deliver packet "
"(s=%s, d=%s)\n", st->name, s, d);
free(s); free(d);
- netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
- ICMP_CODE_NET_UNREACHABLE);
+ netlink_icmp_simple(st,buf,ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_NET_UNREACHABLE, icmp_noinfo);
BUF_FREE(buf);
}
} else {
st->name,s,d);
free(s); free(d);
- netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
- ICMP_CODE_NET_PROHIBITED);
+ netlink_icmp_simple(st,buf,ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_NET_PROHIBITED, icmp_noinfo);
BUF_FREE(buf);
} else {
if (best_quality>0) {
BUF_ASSERT_FREE(buf);
} else {
/* Generate ICMP destination unreachable */
- netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
- ICMP_CODE_NET_UNREACHABLE); /* client==NULL */
+ netlink_icmp_simple(st,buf,
+ ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_NET_UNREACHABLE,
+ icmp_noinfo);
BUF_FREE(buf);
}
}
/* Packet has already been checked */
if (iph->ttl<=1) {
/* Generate ICMP time exceeded */
- netlink_icmp_simple(st,buf,client,ICMP_TYPE_TIME_EXCEEDED,
- ICMP_CODE_TTL_EXCEEDED);
+ netlink_icmp_simple(st,buf,ICMP_TYPE_TIME_EXCEEDED,
+ ICMP_CODE_TTL_EXCEEDED,icmp_noinfo);
BUF_FREE(buf);
return;
}
}
h=(struct icmphdr *)buf->start;
- if ((ntohs(h->iph.frag_off)&0xbfff)!=0) {
+ if ((ntohs(h->iph.frag)&(IPHDR_FRAG_OFF|IPHDR_FRAG_MORE))!=0) {
Message(M_WARNING,"%s: fragmented packet addressed to secnet; "
"ignoring it\n",st->name);
BUF_FREE(buf);
Message(M_WARNING,"%s: unknown incoming ICMP\n",st->name);
} else {
/* Send ICMP protocol unreachable */
- netlink_icmp_simple(st,buf,client,ICMP_TYPE_UNREACHABLE,
- ICMP_CODE_PROTOCOL_UNREACHABLE);
+ netlink_icmp_simple(st,buf,ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_PROTOCOL_UNREACHABLE,icmp_noinfo);
BUF_FREE(buf);
return;
}
address validity and generate ICMP, etc. */
if (st->ptp) {
if (client) {
- st->deliver_to_host(st->dst,buf);
+ netlink_host_deliver(st,source,dest,buf);
} else {
netlink_client_deliver(st,st->clients,source,dest,buf);
}
if (requested) c=M_WARNING;
if (st->ptp) {
net=ipaddr_to_string(st->secnet_address);
- Message(c,"%s: point-to-point (remote end is %s); routes:\n",
+ Message(c,"%s: point-to-point (remote end is %s); routes: ",
st->name, net);
free(net);
netlink_output_subnets(st,c,st->clients->subnets);
~ian / secnet.git / blobdiff