/* User-kernel network link */
-/* Each netlink device is actually a router, with its own IP address.
- We do things like decreasing the TTL and recalculating the header
- checksum, generating ICMP, responding to pings, etc. */
+/* See RFCs 791, 792, 1123 and 1812 */
-/* This is where we have the anti-spoofing paranoia - before sending a
- packet to the kernel we check that the tunnel it came over could
- reasonably have produced it. */
+/* The netlink device is actually a router. Tunnels are unnumbered
+ point-to-point lines (RFC1812 section 2.2.7); the router has a
+ single address (the 'router-id'). */
+/* This is where we currently have the anti-spoofing paranoia - before
+ sending a packet to the kernel we check that the tunnel it came
+ over could reasonably have produced it. */
+
+
+/* Points to note from RFC1812 (which may require changes in this
+ file):
+
+3.3.4 Maximum Transmission Unit - MTU
+
+ The MTU of each logical interface MUST be configurable within the
+ range of legal MTUs for the interface.
+
+ Many Link Layer protocols define a maximum frame size that may be
+ sent. In such cases, a router MUST NOT allow an MTU to be set which
+ would allow sending of frames larger than those allowed by the Link
+ Layer protocol. However, a router SHOULD be willing to receive a
+ packet as large as the maximum frame size even if that is larger than
+ the MTU.
+
+4.2.1 A router SHOULD count datagrams discarded.
+
+4.2.2.1 Source route options - we probably should implement processing
+of source routes, even though mostly the security policy will prevent
+their use.
+
+5.3.13.4 Source Route Options
+
+ A router MUST implement support for source route options in forwarded
+ packets. A router MAY implement a configuration option that, when
+ enabled, causes all source-routed packets to be discarded. However,
+ such an option MUST NOT be enabled by default.
+
+5.3.13.5 Record Route Option
+
+ Routers MUST support the Record Route option in forwarded packets.
+
+ A router MAY provide a configuration option that, if enabled, will
+ cause the router to ignore (i.e., pass through unchanged) Record
+ Route options in forwarded packets. If provided, such an option MUST
+ default to enabling the record-route. This option should not affect
+ the processing of Record Route options in datagrams received by the
+ router itself (in particular, Record Route options in ICMP echo
+ requests will still be processed according to Section [4.3.3.6]).
+
+5.3.13.6 Timestamp Option
+
+ Routers MUST support the timestamp option in forwarded packets. A
+ timestamp value MUST follow the rules given [INTRO:2].
+
+ If the flags field = 3 (timestamp and prespecified address), the
+ router MUST add its timestamp if the next prespecified address
+ matches any of the router's IP addresses. It is not necessary that
+ the prespecified address be either the address of the interface on
+ which the packet arrived or the address of the interface over which
+ it will be sent.
+
+
+4.2.2.7 Fragmentation: RFC 791 Section 3.2
+
+ Fragmentation, as described in [INTERNET:1], MUST be supported by a
+ router.
+
+4.2.2.8 Reassembly: RFC 791 Section 3.2
+
+ As specified in the corresponding section of [INTRO:2], a router MUST
+ support reassembly of datagrams that it delivers to itself.
+
+4.2.2.9 Time to Live: RFC 791 Section 3.2
+
+ Note in particular that a router MUST NOT check the TTL of a packet
+ except when forwarding it.
+
+ A router MUST NOT discard a datagram just because it was received
+ with TTL equal to zero or one; if it is to the router and otherwise
+ valid, the router MUST attempt to receive it.
+
+ On messages the router originates, the IP layer MUST provide a means
+ for the transport layer to set the TTL field of every datagram that
+ is sent. When a fixed TTL value is used, it MUST be configurable.
+
+
+8.1 The Simple Network Management Protocol - SNMP
+8.1.1 SNMP Protocol Elements
+
+ Routers MUST be manageable by SNMP [MGT:3]. The SNMP MUST operate
+ using UDP/IP as its transport and network protocols.
+
+
+*/
+
+#include <string.h>
+#include <assert.h>
+#include <limits.h>
#include "secnet.h"
#include "util.h"
#include "ipaddr.h"
#include "netlink.h"
#include "process.h"
-#define OPT_SOFTROUTE 1
-#define OPT_ALLOWROUTE 2
+#ifdef NETLINK_DEBUG
+#define MDEBUG(...) Message(M_DEBUG, __VA_ARGS__)
+#else /* !NETLINK_DEBUG */
+#define MDEBUG(...) ((void)0)
+#endif /* !NETLINK_DEBUG */
+
+#define ICMP_TYPE_ECHO_REPLY 0
+
+#define ICMP_TYPE_UNREACHABLE 3
+#define ICMP_CODE_NET_UNREACHABLE 0
+#define ICMP_CODE_PROTOCOL_UNREACHABLE 2
+#define ICMP_CODE_FRAGMENTATION_REQUIRED 4
+#define ICMP_CODE_NET_PROHIBITED 13
+
+#define ICMP_TYPE_ECHO_REQUEST 8
+
+#define ICMP_TYPE_TIME_EXCEEDED 11
+#define ICMP_CODE_TTL_EXCEEDED 0
/* Generic IP checksum routine */
-static inline uint16_t ip_csum(uint8_t *iph,uint32_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, uint32_t ihl) {
+static inline uint16_t ip_fast_csum(const uint8_t *iph, int32_t ihl) {
uint32_t sum;
- __asm__ __volatile__("
- movl (%1), %0
- subl $4, %2
- jbe 2f
- addl 4(%1), %0
- adcl 8(%1), %0
- adcl 12(%1), %0
-1: adcl 16(%1), %0
- lea 4(%1), %1
- decl %2
- jne 1b
- adcl $0, %0
- movl %0, %2
- shrl $16, %0
- addw %w2, %w0
- adcl $0, %0
- notl %0
-2:
- "
+ __asm__ __volatile__(
+ "movl (%1), %0 ;\n"
+ "subl $4, %2 ;\n"
+ "jbe 2f ;\n"
+ "addl 4(%1), %0 ;\n"
+ "adcl 8(%1), %0 ;\n"
+ "adcl 12(%1), %0 ;\n"
+"1: adcl 16(%1), %0 ;\n"
+ "lea 4(%1), %1 ;\n"
+ "decl %2 ;\n"
+ "jne 1b ;\n"
+ "adcl $0, %0 ;\n"
+ "movl %0, %2 ;\n"
+ "shrl $16, %0 ;\n"
+ "addw %w2, %w0 ;\n"
+ "adcl $0, %0 ;\n"
+ "notl %0 ;\n"
+"2: ;\n"
/* Since the input registers which are loaded with iph and ipl
are modified, we must also specify them as outputs, or gcc
will assume they contain their original values. */
: "=r" (sum), "=r" (iph), "=r" (ihl)
- : "1" (iph), "2" (ihl));
+ : "1" (iph), "2" (ihl)
+ : "memory");
return sum;
}
#else
-static inline uint16_t ip_fast_csum(uint8_t *iph, uint32_t ihl)
+static inline uint16_t ip_fast_csum(const uint8_t *iph, int32_t ihl)
{
+ assert(ihl < INT_MAX/4);
return ip_csum(iph,ihl*4);
}
#endif
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;
uint16_t id;
uint16_t seq;
} echo;
+ struct {
+ uint16_t unused;
+ uint16_t mtu;
+ } fragneeded;
} d;
};
+
+static const union icmpinfofield icmp_noinfo;
+static void netlink_client_deliver(struct netlink *st,
+ struct netlink_client *client,
+ uint32_t source, uint32_t dest,
+ struct buffer_if *buf);
+static void netlink_host_deliver(struct netlink *st,
+ struct netlink_client *sender,
+ uint32_t source, uint32_t dest,
+ struct buffer_if *buf);
+
+static const char *sender_name(struct netlink_client *sender /* or NULL */)
+{
+ return sender?sender->name:"(local)";
+}
+
static void netlink_packet_deliver(struct netlink *st,
struct netlink_client *client,
struct buffer_if *buf);
+/* XXX RFC1812 4.3.2.5:
+ All other ICMP error messages (Destination Unreachable,
+ Redirect, Time Exceeded, and Parameter Problem) SHOULD have their
+ precedence value set to 6 (INTERNETWORK CONTROL) or 7 (NETWORK
+ CONTROL). The IP Precedence value for these error messages MAY be
+ settable.
+ */
static struct icmphdr *netlink_icmp_tmpl(struct netlink *st,
- uint32_t dest,uint16_t len)
+ uint32_t source, uint32_t dest,
+ uint16_t len)
{
struct icmphdr *h;
BUF_ALLOC(&st->icmp,"netlink_icmp_tmpl");
- buffer_init(&st->icmp,st->max_start_pad);
+ buffer_init(&st->icmp,calculate_max_start_pad());
h=buf_append(&st->icmp,sizeof(*h));
h->iph.version=4;
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.ttl=255;
+ h->iph.frag=0;
+ h->iph.ttl=255; /* XXX should be configurable */
h->iph.protocol=1;
- h->iph.saddr=htonl(st->secnet_address);
+ h->iph.saddr=htonl(source);
h->iph.daddr=htonl(dest);
h->iph.check=0;
h->iph.check=ip_fast_csum((uint8_t *)&h->iph,h->iph.ihl);
/* Fill in the ICMP checksum field correctly */
static void netlink_icmp_csum(struct icmphdr *h)
{
- uint32_t len;
+ int32_t len;
len=ntohs(h->iph.tot_len)-(4*h->iph.ihl);
h->check=0;
struct icmphdr *icmph;
uint32_t source;
+ if (buf->size < (int)sizeof(struct icmphdr)) return False;
iph=(struct iphdr *)buf->start;
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;
/* How much of the original IP packet do we include in its ICMP
response? The header plus up to 64 bits. */
+
+/* XXX TODO RFC1812:
+4.3.2.3 Original Message Header
+
+ Historically, every ICMP error message has included the Internet
+ header and at least the first 8 data bytes of the datagram that
+ triggered the error. This is no longer adequate, due to the use of
+ IP-in-IP tunneling and other technologies. Therefore, the ICMP
+ datagram SHOULD contain as much of the original datagram as possible
+ without the length of the ICMP datagram exceeding 576 bytes. The
+ returned IP header (and user data) MUST be identical to that which
+ was received, except that the router is not required to undo any
+ modifications to the IP header that are normally performed in
+ forwarding that were performed before the error was detected (e.g.,
+ decrementing the TTL, or updating options). Note that the
+ requirements of Section [4.3.3.5] supersede this requirement in some
+ cases (i.e., for a Parameter Problem message, if the problem is in a
+ modified field, the router must undo the modification). See Section
+ [4.3.3.5]).
+ */
static uint16_t netlink_icmp_reply_len(struct buffer_if *buf)
{
+ if (buf->size < (int)sizeof(struct iphdr)) return 0;
struct iphdr *iph=(struct iphdr *)buf->start;
uint16_t hlen,plen;
/* 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)
+static void netlink_icmp_simple(struct netlink *st,
+ struct netlink_client *origsender,
+ struct buffer_if *buf,
+ uint8_t type, uint8_t code,
+ union icmpinfofield info)
{
- struct iphdr *iph=(struct iphdr *)buf->start;
struct icmphdr *h;
uint16_t len;
if (netlink_icmp_may_reply(buf)) {
+ struct iphdr *iph=(struct iphdr *)buf->start;
+
+ uint32_t icmpdest = ntohl(iph->saddr);
+ uint32_t icmpsource;
+ const char *icmpsourcedebugprefix;
+ if (!st->ptp) {
+ icmpsource=st->secnet_address;
+ icmpsourcedebugprefix="";
+ } else if (origsender) {
+ /* was from peer, send reply as if from host */
+ icmpsource=st->local_address;
+ icmpsourcedebugprefix="L!";
+ } else {
+ /* was from host, send reply as if from peer */
+ icmpsource=st->secnet_address; /* actually, peer address */
+ icmpsourcedebugprefix="P!";
+ }
+ MDEBUG("%s: generating ICMP re %s[%s]->[%s]:"
+ " from %s%s type=%u code=%u\n",
+ st->name, sender_name(origsender),
+ ipaddr_to_string(ntohl(iph->saddr)),
+ ipaddr_to_string(ntohl(iph->daddr)),
+ icmpsourcedebugprefix,
+ ipaddr_to_string(icmpsource),
+ type, code);
+
len=netlink_icmp_reply_len(buf);
- h=netlink_icmp_tmpl(st,ntohl(iph->saddr),len);
- h->type=type; h->code=code;
- memcpy(buf_append(&st->icmp,len),buf->start,len);
+ h=netlink_icmp_tmpl(st,icmpsource,icmpdest,len);
+ h->type=type; h->code=code; h->d=info;
+ BUF_ADD_BYTES(append,&st->icmp,buf->start,len);
netlink_icmp_csum(h);
- netlink_packet_deliver(st,NULL,&st->icmp);
+
+ if (!st->ptp) {
+ netlink_packet_deliver(st,NULL,&st->icmp);
+ } else if (origsender) {
+ netlink_client_deliver(st,origsender,icmpsource,icmpdest,&st->icmp);
+ } else {
+ netlink_host_deliver(st,NULL,icmpsource,icmpdest,&st->icmp);
+ }
BUF_ASSERT_FREE(&st->icmp);
}
}
/*
* RFC1122: 3.1.2.2 MUST silently discard any IP frame that fails the
* checksum.
+ * RFC1812: 4.2.2.5 MUST discard messages containing invalid checksums.
*
* Is the datagram acceptable?
*
* 3. Checksums correctly.
* 4. Doesn't have a bogus length
*/
-static bool_t netlink_check(struct netlink *st, struct buffer_if *buf)
+static bool_t netlink_check(struct netlink *st, struct buffer_if *buf,
+ char *errmsgbuf, int errmsgbuflen)
{
+#define BAD(...) do{ \
+ snprintf(errmsgbuf,errmsgbuflen,__VA_ARGS__); \
+ return False; \
+ }while(0)
+
+ if (buf->size < (int)sizeof(struct iphdr)) BAD("len %"PRIu32"",buf->size);
struct iphdr *iph=(struct iphdr *)buf->start;
- uint32_t len;
+ int32_t len;
- if (iph->ihl < 5 || iph->version != 4) return False;
- if (buf->size < iph->ihl*4) return False;
- if (ip_fast_csum((uint8_t *)iph, iph->ihl)!=0) return False;
+ if (iph->ihl < 5) BAD("ihl %u",iph->ihl);
+ if (iph->version != 4) BAD("version %u",iph->version);
+ if (buf->size < iph->ihl*4) BAD("size %"PRId32"<%u*4",buf->size,iph->ihl);
+ if (ip_fast_csum((uint8_t *)iph, iph->ihl)!=0) BAD("csum");
len=ntohs(iph->tot_len);
/* There should be no padding */
- if (buf->size!=len || len<(iph->ihl<<2)) return False;
+ if (buf->size!=len) BAD("len %"PRId32"!=%"PRId32,buf->size,len);
+ if (len<(iph->ihl<<2)) BAD("len %"PRId32"<(%u<<2)",len,iph->ihl);
/* XXX check that there's no source route specified */
return True;
+
+#undef BAD
}
-/* Deliver a packet. "client" is the _origin_ of the packet, not its
-destination. */
-static void netlink_packet_deliver(struct netlink *st,
+static const char *fragment_filter_header(uint8_t *base, long *hlp)
+{
+ const int fixedhl = sizeof(struct iphdr);
+ long hl = *hlp;
+ const uint8_t *ipend = base + hl;
+ uint8_t *op = base + fixedhl;
+ const uint8_t *ip = op;
+
+ while (ip < ipend) {
+ uint8_t opt = ip[0];
+ int remain = ipend - ip;
+ if (opt == 0x00) /* End of Options List */ break;
+ if (opt == 0x01) /* No Operation */ continue;
+ if (remain < 2) return "IPv4 options truncated at length";
+ int optlen = ip[1];
+ if (remain < optlen) return "IPv4 options truncated in option";
+ if (opt & 0x80) /* copy */ {
+ memmove(op, ip, optlen);
+ op += optlen;
+ }
+ ip += optlen;
+ }
+ while ((hl = (op - base)) & 0x3)
+ *op++ = 0x00 /* End of Option List */;
+ ((struct iphdr*)base)->ihl = hl >> 2;
+ *hlp = hl;
+
+ return 0;
+}
+
+/* Fragment or send ICMP Fragmentation Needed */
+static void netlink_maybe_fragment(struct netlink *st,
+ struct netlink_client *sender,
+ netlink_deliver_fn *deliver,
+ void *deliver_dst,
+ const char *delivery_name,
+ int32_t mtu,
+ uint32_t source, uint32_t dest,
+ struct buffer_if *buf)
+{
+ struct iphdr *iph=(struct iphdr*)buf->start;
+ long hl = iph->ihl*4;
+ const char *ssource = ipaddr_to_string(source);
+
+ if (buf->size <= mtu) {
+ deliver(deliver_dst, buf);
+ return;
+ }
+
+ MDEBUG("%s: fragmenting %s->%s org.size=%"PRId32"\n",
+ st->name, ssource, delivery_name, buf->size);
+
+#define BADFRAG(m, ...) \
+ Message(M_WARNING, \
+ "%s: fragmenting packet from source %s" \
+ " for transmission via %s: " m "\n", \
+ st->name, ssource, delivery_name, \
+ ## __VA_ARGS__);
+
+ unsigned orig_frag = ntohs(iph->frag);
+
+ if (orig_frag&IPHDR_FRAG_DONT) {
+ union icmpinfofield info =
+ { .fragneeded = { .unused = 0, .mtu = htons(mtu) } };
+ netlink_icmp_simple(st,sender,buf,
+ ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_FRAGMENTATION_REQUIRED,
+ info);
+ BUF_FREE(buf);
+ return;
+ }
+ if (mtu < hl + 8) {
+ BADFRAG("mtu %"PRId32" too small", mtu);
+ BUF_FREE(buf);
+ return;
+ }
+
+ /* we (ab)use the icmp buffer to stash the original packet */
+ struct buffer_if *orig = &st->icmp;
+ BUF_ALLOC(orig,"netlink_client_deliver fragment orig");
+ buffer_copy(orig,buf);
+ BUF_FREE(buf);
+
+ const uint8_t *startindata = orig->start + hl;
+ const uint8_t *indata = startindata;
+ const uint8_t *endindata = orig->start + orig->size;
+ _Bool filtered = 0;
+
+ for (;;) {
+ /* compute our fragment offset */
+ long dataoffset = indata - startindata
+ + (orig_frag & IPHDR_FRAG_OFF)*8;
+ assert(!(dataoffset & 7));
+ if (dataoffset > IPHDR_FRAG_OFF*8) {
+ BADFRAG("ultimate fragment offset out of range");
+ break;
+ }
+
+ BUF_ALLOC(buf,"netlink_client_deliver fragment frag");
+ buffer_init(buf,calculate_max_start_pad());
+
+ /* copy header (possibly filtered); will adjust in a bit */
+ struct iphdr *fragh = buf_append(buf, hl);
+ memcpy(fragh, orig->start, hl);
+
+ /* decide how much payload to copy and copy it */
+ long avail = mtu - hl;
+ long remain = endindata - indata;
+ long use = avail < remain ? (avail & ~(long)7) : remain;
+ BUF_ADD_BYTES(append, buf, indata, use);
+ indata += use;
+
+ _Bool last_frag = indata >= endindata;
+
+ /* adjust the header */
+ fragh->tot_len = htons(buf->size);
+ fragh->frag =
+ htons((orig_frag & ~IPHDR_FRAG_OFF) |
+ (last_frag ? 0 : IPHDR_FRAG_MORE) |
+ (dataoffset >> 3));
+ fragh->check = 0;
+ fragh->check = ip_fast_csum((const void*)fragh, fragh->ihl);
+
+ /* actually send it */
+ deliver(deliver_dst, buf);
+ if (last_frag)
+ break;
+
+ /* after copying the header for the first frag,
+ * we filter the header for the remaining frags */
+ if (!filtered++) {
+ const char *bad = fragment_filter_header(orig->start, &hl);
+ if (bad) { BADFRAG("%s", bad); break; }
+ }
+ }
+
+ BUF_FREE(orig);
+
+#undef BADFRAG
+}
+
+/* Deliver a packet _to_ client; used after we have decided
+ * what to do with it (and just to check that the client has
+ * actually registered a delivery function with us). */
+static void netlink_client_deliver(struct netlink *st,
struct netlink_client *client,
+ uint32_t source, uint32_t dest,
struct buffer_if *buf)
{
+ if (!client->deliver) {
+ string_t s,d;
+ s=ipaddr_to_string(source);
+ d=ipaddr_to_string(dest);
+ Message(M_ERR,"%s: dropping %s->%s, client not registered\n",
+ st->name,s,d);
+ BUF_FREE(buf);
+ return;
+ }
+ netlink_maybe_fragment(st,NULL, client->deliver,client->dst,client->name,
+ client->mtu, source,dest,buf);
+ 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,
+ struct netlink_client *sender,
+ uint32_t source, uint32_t dest,
+ struct buffer_if *buf)
+{
+ netlink_maybe_fragment(st,sender, st->deliver_to_host,st->dst,"(host)",
+ st->mtu, source,dest,buf);
+ st->outcount++;
+}
+
+/* Deliver a packet. "sender"==NULL for packets from the host and packets
+ generated internally in secnet. */
+static void netlink_packet_deliver(struct netlink *st,
+ struct netlink_client *sender,
+ struct buffer_if *buf)
+{
+ if (buf->size < (int)sizeof(struct iphdr)) {
+ Message(M_ERR,"%s: trying to deliver a too-short packet"
+ " from %s!\n",st->name, sender_name(sender));
+ BUF_FREE(buf);
+ return;
+ }
+
struct iphdr *iph=(struct iphdr *)buf->start;
uint32_t dest=ntohl(iph->daddr);
uint32_t source=ntohl(iph->saddr);
BUF_ASSERT_USED(buf);
if (dest==st->secnet_address) {
- Message(M_ERR,"%s: trying to deliver a packet to myself!\n");
+ Message(M_ERR,"%s: trying to deliver a packet to myself!\n",st->name);
BUF_FREE(buf);
return;
}
- /* Packets from the host (client==NULL) will always be routed. Packets
+ /* Packets from the host (sender==NULL) may always be routed. Packets
from clients with the allow_route option will also be routed. */
- if (!client || (client && (client->options & OPT_ALLOWROUTE)))
+ if (!sender || (sender && (sender->options & OPT_ALLOWROUTE)))
allow_route=True;
/* If !allow_route, we check the routing table anyway, and if
best_quality=0;
best_match=-1;
- for (i=0; i<st->n_routes; i++) {
- if (st->routes[i].up && subnet_match(st->routes[i].net,dest)) {
+ for (i=0; i<st->n_clients; i++) {
+ if (st->routes[i]->up &&
+ ipset_contains_addr(st->routes[i]->networks,dest)) {
/* It's an available route to the correct destination. But is
it better than the one we already have? */
bother looking at routes we're not allowed to use. If
we don't yet have an allowed route we'll consider any. */
if (!allow_route && found_allowed) {
- if (!(st->routes[i].c->options&OPT_ALLOWROUTE)) continue;
+ if (!(st->routes[i]->options&OPT_ALLOWROUTE)) continue;
}
- if (st->routes[i].c->link_quality>best_quality
+ if (st->routes[i]->link_quality>best_quality
|| best_quality==0) {
- best_quality=st->routes[i].c->link_quality;
+ best_quality=st->routes[i]->link_quality;
best_match=i;
- if (st->routes[i].c->options&OPT_ALLOWROUTE)
+ if (st->routes[i]->options&OPT_ALLOWROUTE)
found_allowed=True;
/* If quality isn't perfect we may wish to
consider kicking the tunnel with a 0-length
/* 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,sender,source,dest,buf);
BUF_ASSERT_FREE(buf);
} else {
string_t s,d;
s=ipaddr_to_string(source);
d=ipaddr_to_string(dest);
- Message(M_ERR,"%s: don't know where to deliver packet "
+ 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,3,0);
+ netlink_icmp_simple(st,sender,buf,ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_NET_UNREACHABLE, icmp_noinfo);
BUF_FREE(buf);
}
} else {
if (!allow_route &&
- !(st->routes[best_match].c->options&OPT_ALLOWROUTE)) {
+ !(st->routes[best_match]->options&OPT_ALLOWROUTE)) {
string_t s,d;
s=ipaddr_to_string(source);
d=ipaddr_to_string(dest);
with destination network administratively prohibited */
Message(M_NOTICE,"%s: denied forwarding for packet (s=%s, d=%s)\n",
st->name,s,d);
- free(s); free(d);
- netlink_icmp_simple(st,buf,client,3,9);
+ netlink_icmp_simple(st,sender,buf,ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_NET_PROHIBITED, icmp_noinfo);
BUF_FREE(buf);
- }
- if (best_quality>0) {
- st->routes[best_match].c->deliver(
- st->routes[best_match].c->dst, buf);
- st->routes[best_match].outcount++;
- BUF_ASSERT_FREE(buf);
} else {
- /* Generate ICMP destination unreachable */
- netlink_icmp_simple(st,buf,client,3,0); /* client==NULL */
- BUF_FREE(buf);
+ if (best_quality>0) {
+ netlink_client_deliver(st,st->routes[best_match],
+ source,dest,buf);
+ BUF_ASSERT_FREE(buf);
+ } else {
+ /* Generate ICMP destination unreachable */
+ netlink_icmp_simple(st,sender,buf,
+ ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_NET_UNREACHABLE,
+ icmp_noinfo);
+ BUF_FREE(buf);
+ }
}
}
BUF_ASSERT_FREE(buf);
}
static void netlink_packet_forward(struct netlink *st,
- struct netlink_client *client,
+ struct netlink_client *sender,
struct buffer_if *buf)
{
+ if (buf->size < (int)sizeof(struct iphdr)) return;
struct iphdr *iph=(struct iphdr *)buf->start;
BUF_ASSERT_USED(buf);
/* Packet has already been checked */
if (iph->ttl<=1) {
/* Generate ICMP time exceeded */
- netlink_icmp_simple(st,buf,client,11,0);
+ netlink_icmp_simple(st,sender,buf,ICMP_TYPE_TIME_EXCEEDED,
+ ICMP_CODE_TTL_EXCEEDED,icmp_noinfo);
BUF_FREE(buf);
return;
}
iph->check=0;
iph->check=ip_fast_csum((uint8_t *)iph,iph->ihl);
- netlink_packet_deliver(st,client,buf);
+ netlink_packet_deliver(st,sender,buf);
BUF_ASSERT_FREE(buf);
}
/* Deal with packets addressed explicitly to us */
static void netlink_packet_local(struct netlink *st,
- struct netlink_client *client,
+ struct netlink_client *sender,
struct buffer_if *buf)
{
struct icmphdr *h;
st->localcount++;
+ if (buf->size < (int)sizeof(struct icmphdr)) {
+ Message(M_WARNING,"%s: short packet addressed to secnet; "
+ "ignoring it\n",st->name);
+ BUF_FREE(buf);
+ return;
+ }
h=(struct icmphdr *)buf->start;
- if ((ntohs(h->iph.frag_off)&0xbfff)!=0) {
- Message(M_WARNING,"%s: fragmented packet addressed to secnet; "
- "ignoring it\n",st->name);
+ unsigned fraginfo = ntohs(h->iph.frag);
+ if ((fraginfo&(IPHDR_FRAG_OFF|IPHDR_FRAG_MORE))!=0) {
+ if (!(fraginfo & IPHDR_FRAG_OFF))
+ /* report only for first fragment */
+ Message(M_WARNING,"%s: fragmented packet addressed to secnet; "
+ "ignoring it\n",st->name);
BUF_FREE(buf);
return;
}
if (h->iph.protocol==1) {
/* It's ICMP */
- if (h->type==8 && h->code==0) {
+ if (h->type==ICMP_TYPE_ECHO_REQUEST && h->code==0) {
/* ICMP echo-request. Special case: we re-use the buffer
to construct the reply. */
- h->type=0;
+ h->type=ICMP_TYPE_ECHO_REPLY;
h->iph.daddr=h->iph.saddr;
h->iph.saddr=htonl(st->secnet_address);
- h->iph.ttl=255; /* Be nice and bump it up again... */
+ h->iph.ttl=255;
h->iph.check=0;
h->iph.check=ip_fast_csum((uint8_t *)h,h->iph.ihl);
netlink_icmp_csum(h);
Message(M_WARNING,"%s: unknown incoming ICMP\n",st->name);
} else {
/* Send ICMP protocol unreachable */
- netlink_icmp_simple(st,buf,client,3,2);
+ netlink_icmp_simple(st,sender,buf,ICMP_TYPE_UNREACHABLE,
+ ICMP_CODE_PROTOCOL_UNREACHABLE,icmp_noinfo);
BUF_FREE(buf);
return;
}
/* If cid==NULL packet is from host, otherwise cid specifies which tunnel
it came from. */
-static void netlink_incoming(struct netlink *st, struct netlink_client *client,
+static void netlink_incoming(struct netlink *st, struct netlink_client *sender,
struct buffer_if *buf)
{
uint32_t source,dest;
struct iphdr *iph;
+ char errmsgbuf[50];
+ const char *sourcedesc=sender?sender->name:"host";
BUF_ASSERT_USED(buf);
- if (!netlink_check(st,buf)) {
- Message(M_WARNING,"%s: bad IP packet from %s\n",
- st->name,client?client->name:"host");
+
+ if (!netlink_check(st,buf,errmsgbuf,sizeof(errmsgbuf))) {
+ Message(M_WARNING,"%s: bad IP packet from %s: %s\n",
+ st->name,sourcedesc,
+ errmsgbuf);
BUF_FREE(buf);
return;
}
+ assert(buf->size >= (int)sizeof(struct iphdr));
iph=(struct iphdr *)buf->start;
source=ntohl(iph->saddr);
dest=ntohl(iph->daddr);
- /* Check source */
- /* XXX consider generating ICMP if we're not point-to-point and we
- don't like the packet */
- if (client) {
+ /* Check source. If we don't like the source, there's no point
+ generating ICMP because we won't know how to get it to the
+ source of the packet. */
+ if (sender) {
/* Check that the packet source is appropriate for the tunnel
it came down */
- if (!ipset_contains_addr(client->networks,source)) {
+ if (!ipset_contains_addr(sender->networks,source)) {
string_t s,d;
s=ipaddr_to_string(source);
d=ipaddr_to_string(dest);
Message(M_WARNING,"%s: packet from tunnel %s with bad "
- "source address (s=%s,d=%s)\n",st->name,client->name,s,d);
- free(s); free(d);
+ "source address (s=%s,d=%s)\n",st->name,sender->name,s,d);
BUF_FREE(buf);
return;
}
d=ipaddr_to_string(dest);
Message(M_WARNING,"%s: outgoing packet with bad source address "
"(s=%s,d=%s)\n",st->name,s,d);
- free(s); free(d);
BUF_FREE(buf);
return;
}
/* If this is a point-to-point device we don't examine the
destination address at all; we blindly send it down our
one-and-only registered tunnel, or to the host, depending on
- where it came from. */
- /* XXX I think we should check destination addresses */
+ where it came from. It's up to external software to check
+ address validity and generate ICMP, etc. */
if (st->ptp) {
- if (client) {
- st->deliver_to_host(st->dst,buf);
+ if (sender) {
+ netlink_host_deliver(st,sender,source,dest,buf);
} else {
- st->clients->deliver(st->clients->dst,buf);
+ netlink_client_deliver(st,st->clients,source,dest,buf);
}
BUF_ASSERT_FREE(buf);
return;
}
- /* (st->secnet_address needs checking before matching destination
- addresses) */
+ /* st->secnet_address needs checking before matching destination
+ addresses */
if (dest==st->secnet_address) {
- netlink_packet_local(st,client,buf);
+ netlink_packet_local(st,sender,buf);
BUF_ASSERT_FREE(buf);
return;
}
- netlink_packet_forward(st,client,buf);
+ netlink_packet_forward(st,sender,buf);
BUF_ASSERT_FREE(buf);
}
netlink_incoming(st,NULL,buf);
}
-static void netlink_set_softlinks(struct netlink *st, struct netlink_client *c,
- bool_t up, uint32_t quality)
+static void netlink_set_quality(void *sst, uint32_t quality)
{
- uint32_t i;
+ struct netlink_client *c=sst;
+ struct netlink *st=c->nst;
- if (!st->routes) return; /* Table has not yet been created */
- for (i=0; i<st->n_routes; i++) {
- if (st->routes[i].c==c) {
- st->routes[i].quality=quality;
- if (!st->routes[i].hard) {
- st->routes[i].up=up;
- st->set_route(st->dst,&st->routes[i]);
- }
- }
+ c->link_quality=quality;
+ c->up=(c->link_quality==LINK_QUALITY_DOWN)?False:True;
+ if (c->options&OPT_SOFTROUTE) {
+ st->set_routes(st->dst,c);
}
}
-static void netlink_set_quality(void *sst, uint32_t quality)
+static void netlink_output_subnets(struct netlink *st, uint32_t loglevel,
+ struct subnet_list *snets)
{
- struct netlink_client *c=sst;
- struct netlink *st=c->nst;
+ int32_t i;
+ string_t net;
- c->link_quality=quality;
- if (c->link_quality==LINK_QUALITY_DOWN) {
- netlink_set_softlinks(st,c,False,c->link_quality);
- } else {
- netlink_set_softlinks(st,c,True,c->link_quality);
+ for (i=0; i<snets->entries; i++) {
+ net=subnet_to_string(snets->list[i]);
+ Message(loglevel,"%s ",net);
}
}
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);
- for (i=0; i<st->n_routes; i++) {
- net=subnet_to_string(st->routes[i].net);
- Message(c,"%s ",net);
- free(net);
- }
+ netlink_output_subnets(st,c,st->clients->subnets);
Message(c,"\n");
} else {
Message(c,"%s: routing table:\n",st->name);
- for (i=0; i<st->n_routes; i++) {
- net=subnet_to_string(st->routes[i].net);
- Message(c,"%s -> tunnel %s (%s,%s route,%s,quality %d,use %d)\n",net,
- st->routes[i].c->name,
- st->routes[i].hard?"hard":"soft",
- st->routes[i].allow_route?"free":"restricted",
- st->routes[i].up?"up":"down",
- st->routes[i].quality,
- st->routes[i].outcount);
- free(net);
+ for (i=0; i<st->n_clients; i++) {
+ netlink_output_subnets(st,c,st->routes[i]->subnets);
+ Message(c,"-> tunnel %s (%s,mtu %d,%s routes,%s,"
+ "quality %d,use %d,pri %lu)\n",
+ st->routes[i]->name,
+ st->routes[i]->up?"up":"down",
+ st->routes[i]->mtu,
+ st->routes[i]->options&OPT_SOFTROUTE?"soft":"hard",
+ st->routes[i]->options&OPT_ALLOWROUTE?"free":"restricted",
+ st->routes[i]->link_quality,
+ st->routes[i]->outcount,
+ (unsigned long)st->routes[i]->priority);
}
net=ipaddr_to_string(st->secnet_address);
Message(c,"%s/32 -> netlink \"%s\" (use %d)\n",
net,st->name,st->localcount);
- free(net);
for (i=0; i<st->subnets->entries; i++) {
net=subnet_to_string(st->subnets->list[i]);
Message(c,"%s ",net);
- free(net);
}
if (i>0)
Message(c,"-> host (use %d)\n",st->outcount);
}
}
-static int netlink_compare_route_specificity(const void *ap, const void *bp)
+/* ap is a pointer to a member of the routes array */
+static int netlink_compare_client_priority(const void *ap, const void *bp)
{
- const struct netlink_route *a=ap;
- const struct netlink_route *b=bp;
+ const struct netlink_client *const*a=ap;
+ const struct netlink_client *const*b=bp;
- if (a->net.len==b->net.len) return 0;
- if (a->net.len<b->net.len) return 1;
+ if ((*a)->priority==(*b)->priority) return 0;
+ if ((*a)->priority<(*b)->priority) return 1;
return -1;
}
{
struct netlink *st=sst;
struct netlink_client *c;
- uint32_t i,j;
+ int32_t i;
/* All the networks serviced by the various tunnels should now
* have been registered. We build a routing table by sorting the
- * routes into most-specific-first order. */
- st->routes=safe_malloc(st->n_routes*sizeof(*st->routes),
- "netlink_phase_hook");
+ * clients by priority. */
+ st->routes=safe_malloc_ary(sizeof(*st->routes),st->n_clients,
+ "netlink_phase_hook");
/* Fill the table */
i=0;
for (c=st->clients; c; c=c->next) {
- for (j=0; j<c->subnets->entries; j++) {
- st->routes[i].net=c->subnets->list[j];
- st->routes[i].c=c;
- /* Hard routes are always up;
- soft routes default to down; routes with no 'deliver' function
- default to down */
- st->routes[i].up=c->deliver?
- (c->options&OPT_SOFTROUTE?False:True):
- False;
- st->routes[i].kup=False;
- st->routes[i].hard=c->options&OPT_SOFTROUTE?False:True;
- st->routes[i].allow_route=c->options&OPT_ALLOWROUTE?
- True:False;
- st->routes[i].quality=c->link_quality;
- st->routes[i].outcount=0;
- i++;
- }
+ assert(i<INT_MAX);
+ st->routes[i++]=c;
}
- /* ASSERT i==st->n_routes */
- if (i!=st->n_routes) {
- fatal("netlink: route count error: expected %d got %d\n",
- st->n_routes,i);
- }
- /* Sort the table in descending order of specificity */
- qsort(st->routes,st->n_routes,sizeof(*st->routes),
- netlink_compare_route_specificity);
+ /* Sort the table in descending order of priority */
+ qsort(st->routes,st->n_clients,sizeof(*st->routes),
+ netlink_compare_client_priority);
netlink_dump_routes(st,False);
}
netlink_dump_routes(st,True);
}
-static void netlink_inst_output_config(void *sst, struct buffer_if *buf)
+static void netlink_inst_set_mtu(void *sst, int32_t new_mtu)
{
-/* struct netlink_client *c=sst; */
-/* struct netlink *st=c->nst; */
-
- /* For now we don't output anything */
- BUF_ASSERT_USED(buf);
-}
-
-static bool_t netlink_inst_check_config(void *sst, struct buffer_if *buf)
-{
-/* struct netlink_client *c=sst; */
-/* struct netlink *st=c->nst; */
+ struct netlink_client *c=sst;
- BUF_ASSERT_USED(buf);
- /* We need to eat all of the configuration information from the buffer
- for backward compatibility. */
- buf->size=0;
- return True;
+ c->mtu=new_mtu;
}
static void netlink_inst_reg(void *sst, netlink_deliver_fn *deliver,
- void *dst, uint32_t max_start_pad,
- uint32_t max_end_pad)
+ void *dst, uint32_t *localmtu_r)
{
struct netlink_client *c=sst;
struct netlink *st=c->nst;
- if (max_start_pad > st->max_start_pad) st->max_start_pad=max_start_pad;
- if (max_end_pad > st->max_end_pad) st->max_end_pad=max_end_pad;
c->deliver=deliver;
c->dst=dst;
+
+ if (localmtu_r)
+ *localmtu_r=st->mtu;
}
static struct flagstr netlink_option_table[]={
struct netlink_client *c;
string_t name;
struct ipset *networks;
- uint32_t options;
+ uint32_t options,priority;
+ int32_t mtu;
list_t *l;
name=dict_read_string(dict, "name", True, st->name, loc);
options=string_list_to_word(dict_lookup(dict,"options"),
netlink_option_table,st->name);
- if ((options&OPT_SOFTROUTE) && !st->set_route) {
+ priority=dict_read_number(dict,"priority",False,st->name,loc,0);
+ mtu=dict_read_number(dict,"mtu",False,st->name,loc,0);
+
+ if ((options&OPT_SOFTROUTE) && !st->set_routes) {
cfgfatal(loc,st->name,"this netlink device does not support "
"soft routes.\n");
return NULL;
c->ops.reg=netlink_inst_reg;
c->ops.deliver=netlink_inst_incoming;
c->ops.set_quality=netlink_set_quality;
- c->ops.output_config=netlink_inst_output_config;
- c->ops.check_config=netlink_inst_check_config;
+ c->ops.set_mtu=netlink_inst_set_mtu;
c->nst=st;
c->networks=networks;
c->subnets=ipset_to_subnet_list(networks);
+ c->priority=priority;
c->deliver=NULL;
c->dst=NULL;
c->name=name;
+ c->link_quality=LINK_QUALITY_UNUSED;
+ c->mtu=mtu?mtu:st->mtu;
c->options=options;
- c->link_quality=LINK_QUALITY_DOWN;
+ c->outcount=0;
+ c->up=False;
+ c->kup=False;
c->next=st->clients;
st->clients=c;
- st->n_routes+=c->subnets->entries;
+ assert(st->n_clients < INT_MAX);
+ st->n_clients++;
return &c->cl;
}
netlink_deliver_fn *netlink_init(struct netlink *st,
void *dst, struct cloc loc,
- dict_t *dict, string_t description,
- netlink_route_fn *set_route,
+ dict_t *dict, cstring_t description,
+ netlink_route_fn *set_routes,
netlink_deliver_fn *to_host)
{
item_t *sa, *ptpa;
st->cl.type=CL_PURE;
st->cl.apply=netlink_inst_apply;
st->cl.interface=st;
- st->max_start_pad=0;
- st->max_end_pad=0;
st->clients=NULL;
- st->set_route=set_route;
+ st->routes=NULL;
+ st->n_clients=0;
+ st->set_routes=set_routes;
st->deliver_to_host=to_host;
st->name=dict_read_string(dict,"name",False,description,loc);
if (l)
st->networks=string_list_to_ipset(l,loc,st->name,"networks");
else {
- Message(M_WARNING,"%s: no local networks (parameter \"networks\") "
- "defined\n",st->name);
- st->networks=ipset_new();
+ struct ipset *empty;
+ empty=ipset_new();
+ st->networks=ipset_complement(empty);
+ ipset_free(empty);
}
l=dict_lookup(dict,"remote-networks");
if (l) {
st->remote_networks=ipset_complement(empty);
ipset_free(empty);
}
+ st->local_address=string_item_to_ipaddr(
+ dict_find_item(dict,"local-address", True, "netlink", loc),"netlink");
sa=dict_find_item(dict,"secnet-address",False,"netlink",loc);
ptpa=dict_find_item(dict,"ptp-address",False,"netlink",loc);
st->secnet_address=string_item_to_ipaddr(ptpa,"netlink");
st->ptp=True;
}
- /* XXX we may want to subtract secnet_address from networks here, to
- be strictly correct. It shouldn't make any practical difference,
+ /* To be strictly correct we could subtract secnet_address from
+ networks here. It shouldn't make any practical difference,
though, and will make the route dump look complicated... */
st->subnets=ipset_to_subnet_list(st->networks);
st->mtu=dict_read_number(dict, "mtu", False, "netlink", loc, DEFAULT_MTU);
- buffer_new(&st->icmp,ICMP_BUFSIZE);
- st->n_routes=0;
- st->routes=NULL;
+ buffer_new(&st->icmp,MAX(ICMP_BUFSIZE,st->mtu));
st->outcount=0;
st->localcount=0;
struct netlink nl;
};
-static bool_t null_set_route(void *sst, struct netlink_route *route)
+static bool_t null_set_route(void *sst, struct netlink_client *routes)
{
struct null *st=sst;
- string_t t;
-
- if (route->up!=route->kup) {
- t=subnet_to_string(route->net);
- Message(M_INFO,"%s: setting route %s to state %s\n",st->nl.name,
- t, route->up?"up":"down");
- free(t);
- route->kup=route->up;
+
+ if (routes->up!=routes->kup) {
+ Message(M_INFO,"%s: setting routes for tunnel %s to state %s\n",
+ st->nl.name,routes->name,
+ routes->up?"up":"down");
+ routes->kup=routes->up;
return True;
}
return False;
return new_closure(&st->nl.cl);
}
-init_module netlink_module;
void netlink_module(dict_t *dict)
{
add_closure(dict,"null-netlink",null_apply);
~ian / secnet.git / blobdiff