/* User-kernel network link */
-/* We support a variety of methods: userv-ipif, ipif on its own (when
- we run as root), SLIP to a pty, an external netlink daemon. There
- is a performance/security tradeoff. */
+/* We will eventually support a variety of methods for extracting
+ packets from the kernel: userv-ipif, ipif on its own (when we run
+ as root), the kernel TUN driver, SLIP to a pty, an external netlink
+ daemon. There is a performance/security tradeoff. */
/* When dealing with SLIP (to a pty, or ipif) we have separate rx, tx
and client buffers. When receiving we may read() any amount, not
and may be part-way through receiving. */
/* Each netlink device is actually a router, with its own IP
- address. We should eventually do things like decreasing the TTL and
- recalculating the header checksum, generating ICMP, responding to
- pings, etc. but for now we can get away without them. We should
- implement this stuff no matter how we get the packets to/from the
- kernel. */
+ address. We do things like decreasing the TTL and recalculating the
+ header checksum, generating ICMP, responding to pings, etc. */
/* 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. */
+/* XXX now implement TUN. Kernel needs recompiling. */
+
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
+#include <sys/ioctl.h>
+#include "config.h"
#include "secnet.h"
#include "util.h"
+#ifdef HAVE_LINUX_IF_H
+#include <linux/if.h>
+#include <linux/if_tun.h>
+#endif
+
+/* XXX where do we find if_tun on other architectures? */
+
#define DEFAULT_BUFSIZE 2048
+#define DEFAULT_MTU 1000
+#define ICMP_BUFSIZE 1024
#define SLIP_END 192
#define SLIP_ESC 219
struct subnet_list *networks;
netlink_deliver_fn *deliver;
void *dst;
+ string_t name;
+ bool_t can_deliver;
struct netlink_client *next;
};
-struct userv {
+/* Netlink provides one function to the device driver, to call to deliver
+ a packet from the device. The device driver provides one function to
+ netlink, for it to call to deliver a packet to the device. */
+
+struct netlink {
closure_t cl;
struct netlink_if ops;
+ void *dst; /* Pointer to host interface state */
+ string_t name;
uint32_t max_start_pad;
uint32_t max_end_pad;
- int txfd; /* We transmit to userv */
- int rxfd; /* We receive from userv */
- struct netlink_client *clients;
- string_t name;
- string_t userv_path;
- string_t service_user;
- string_t service_name;
struct subnet_list networks;
- uint32_t local_address;
- uint32_t secnet_address;
+ uint32_t local_address; /* host interface address */
+ uint32_t secnet_address; /* our own address */
uint32_t mtu;
- uint32_t txbuflen;
- struct buffer_if *buff; /* We unstuff received packets into here
- and send them to the site code. */
- bool_t pending_esc;
+ struct netlink_client *clients;
+ netlink_deliver_fn *deliver_to_host; /* Provided by driver */
+ struct buffer_if icmp; /* Buffer for assembly of outgoing ICMP */
};
-static int userv_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
- int *timeout_io, const struct timeval *tv_now,
- uint64_t *now)
+/* Generic IP checksum routine */
+static inline uint16_t ip_csum(uint8_t *iph,uint32_t count)
{
- struct userv *st=sst;
- *nfds_io=2;
- fds[0].fd=st->txfd;
- fds[0].events=POLLERR; /* Might want to pick up POLLOUT sometime */
- fds[1].fd=st->rxfd;
- fds[1].events=POLLIN|POLLERR|POLLHUP;
- return 0;
+ register uint32_t sum=0;
+
+ while (count>1) {
+ sum+=ntohs(*(uint16_t *)iph);
+ iph+=2;
+ count-=2;
+ }
+ if(count>0)
+ sum+=*(uint8_t *)iph;
+ while (sum>>16)
+ sum=(sum&0xffff)+(sum>>16);
+ return htons(~sum);
}
-static void process_local_packet(struct userv *st)
+#ifdef i386
+/*
+ * This is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksum on 4 octet boundaries.
+ *
+ * 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) {
+ 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:
+ "
+ /* 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));
+ return sum;
+}
+#else
+static inline uint16_t ip_fast_csum(uint8_t *iph, uint32_t ihl)
{
- uint32_t source,dest;
+ return ip_csum(iph,ihl*4);
+}
+#endif
+
+struct iphdr {
+#if defined (WORDS_BIGENDIAN)
+ uint8_t version:4,
+ ihl:4;
+#else
+ uint8_t ihl:4,
+ version:4;
+#endif
+ uint8_t tos;
+ uint16_t tot_len;
+ uint16_t id;
+ uint16_t frag_off;
+ uint8_t ttl;
+ uint8_t protocol;
+ uint16_t check;
+ uint32_t saddr;
+ uint32_t daddr;
+ /* The options start here. */
+};
+
+struct icmphdr {
+ struct iphdr iph;
+ uint8_t type;
+ uint8_t code;
+ uint16_t check;
+ union {
+ uint32_t unused;
+ struct {
+ uint8_t pointer;
+ uint8_t unused1;
+ uint16_t unused2;
+ } pprob;
+ uint32_t gwaddr;
+ struct {
+ uint16_t id;
+ uint16_t seq;
+ } echo;
+ } d;
+};
+
+static void netlink_packet_deliver(struct netlink *st, struct buffer_if *buf);
+
+static struct icmphdr *netlink_icmp_tmpl(struct netlink *st,
+ uint32_t dest,uint16_t len)
+{
+ struct icmphdr *h;
+
+ BUF_ALLOC(&st->icmp,"netlink_icmp_tmpl");
+ buffer_init(&st->icmp,st->max_start_pad);
+ h=buf_append(&st->icmp,sizeof(*h));
+
+ h->iph.version=4;
+ h->iph.ihl=5;
+ 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.protocol=1;
+ h->iph.saddr=htonl(st->secnet_address);
+ h->iph.daddr=htonl(dest);
+ h->iph.check=0;
+ h->iph.check=ip_fast_csum((uint8_t *)&h->iph,h->iph.ihl);
+ h->check=0;
+ h->d.unused=0;
+
+ return h;
+}
+
+/* Fill in the ICMP checksum field correctly */
+static void netlink_icmp_csum(struct icmphdr *h)
+{
+ uint32_t len;
+
+ len=ntohs(h->iph.tot_len)-(4*h->iph.ihl);
+ h->check=0;
+ h->check=ip_csum(&h->type,len);
+}
+
+/* RFC1122:
+ * An ICMP error message MUST NOT be sent as the result of
+ * receiving:
+ *
+ * * an ICMP error message, or
+ *
+ * * a datagram destined to an IP broadcast or IP multicast
+ * address, or
+ *
+ * * a datagram sent as a link-layer broadcast, or
+ *
+ * * a non-initial fragment, or
+ *
+ * * a datagram whose source address does not define a single
+ * host -- e.g., a zero address, a loopback address, a
+ * broadcast address, a multicast address, or a Class E
+ * address.
+ */
+static bool_t netlink_icmp_may_reply(struct buffer_if *buf)
+{
+ struct iphdr *iph;
+ uint32_t source;
+
+ iph=(struct iphdr *)buf->start;
+ if (iph->protocol==1) return False; /* Overly-broad; we may reply to
+ eg. icmp echo-request */
+ /* How do we spot broadcast destination addresses? */
+ if (ntohs(iph->frag_off)&0x1fff) return False; /* Non-initial fragment */
+ source=ntohl(iph->saddr);
+ if (source==0) return False;
+ if ((source&0xff000000)==0x7f000000) return False;
+ /* How do we spot broadcast source addresses? */
+ if ((source&0xf0000000)==0xe0000000) return False; /* Multicast */
+ if ((source&0xf0000000)==0xf0000000) return False; /* Class E */
+ return True;
+}
+
+/* How much of the original IP packet do we include in its ICMP
+ response? The header plus up to 64 bits. */
+static uint16_t netlink_icmp_reply_len(struct buffer_if *buf)
+{
+ struct iphdr *iph=(struct iphdr *)buf->start;
+ uint16_t hlen,plen;
+
+ hlen=iph->ihl*4;
+ /* We include the first 8 bytes of the packet data, provided they exist */
+ hlen+=8;
+ plen=ntohs(iph->tot_len);
+ return (hlen>plen?plen:hlen);
+}
+
+static void netlink_icmp_simple(struct netlink *st, struct buffer_if *buf,
+ uint8_t type, uint8_t code)
+{
+ struct iphdr *iph=(struct iphdr *)buf->start;
+ struct icmphdr *h;
+ uint16_t len;
+
+ if (netlink_icmp_may_reply(buf)) {
+ 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);
+ netlink_icmp_csum(h);
+ netlink_packet_deliver(st,&st->icmp);
+ BUF_ASSERT_FREE(&st->icmp);
+ }
+}
+
+/*
+ * RFC1122: 3.1.2.2 MUST silently discard any IP frame that fails the
+ * checksum.
+ *
+ * Is the datagram acceptable?
+ *
+ * 1. Length at least the size of an ip header
+ * 2. Version of 4
+ * 3. Checksums correctly.
+ * 4. Doesn't have a bogus length
+ */
+static bool_t netlink_check(struct netlink *st, struct buffer_if *buf)
+{
+ struct iphdr *iph=(struct iphdr *)buf->start;
+ uint32_t len;
+
+ if (iph->ihl < 5 || iph->version != 4) {
+ printf("ihl/version check failed\n");
+ return False;
+ }
+ if (buf->size < iph->ihl*4) {
+ printf("buffer size check failed\n");
+ return False;
+ }
+ if (ip_fast_csum((uint8_t *)iph, iph->ihl)!=0) {
+ printf("checksum failed\n");
+ return False;
+ }
+ len=ntohs(iph->tot_len);
+ /* There should be no padding */
+ if (buf->size!=len || len<(iph->ihl<<2)) {
+ printf("length check failed buf->size=%d len=%d\n",buf->size,len);
+ return False;
+ }
+
+ /* XXX check that there's no source route specified */
+ return True;
+}
+
+static void netlink_packet_deliver(struct netlink *st, struct buffer_if *buf)
+{
+ struct iphdr *iph=(struct iphdr *)buf->start;
+ uint32_t dest=ntohl(iph->daddr);
struct netlink_client *c;
- source=ntohl(*(uint32_t *)(st->buff->start+12));
- dest=ntohl(*(uint32_t *)(st->buff->start+16));
+ BUF_ASSERT_USED(buf);
-/* printf("process_local_packet source=%s dest=%s len=%d\n",
- ipaddr_to_string(source),ipaddr_to_string(dest),
- st->buff->size); */
- if (!subnet_match(&st->networks,source)) {
- string_t s,d;
- s=ipaddr_to_string(source);
- 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);
+ if (dest==st->secnet_address) {
+ Message(M_ERROR,"%s: trying to deliver a packet to myself!\n");
+ BUF_FREE(buf);
return;
}
+
for (c=st->clients; c; c=c->next) {
if (subnet_match(c->networks,dest)) {
- c->deliver(c->dst,c,st->buff);
- BUF_ALLOC(st->buff,"netlink:process_local_packet");
+ if (c->can_deliver) {
+ c->deliver(c->dst,c,buf);
+ BUF_ASSERT_FREE(buf);
+ } else {
+ /* Generate ICMP destination unreachable */
+ netlink_icmp_simple(st,buf,3,0);
+ BUF_FREE(buf);
+ }
return;
}
}
+ if (subnet_match(&st->networks,dest)) {
+ st->deliver_to_host(st->dst,NULL,buf);
+ BUF_ASSERT_FREE(buf);
+ return;
+ }
+ Message(M_ERROR,"%s: failed to deliver a packet (bad destination address)"
+ "\nXXX make this message clearer\n");
+ BUF_FREE(buf);
+}
+
+static void netlink_packet_forward(struct netlink *st, struct buffer_if *buf)
+{
+ 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,11,0);
+ BUF_FREE(buf);
+ return;
+ }
+ iph->ttl--;
+ iph->check=0;
+ iph->check=ip_fast_csum((uint8_t *)iph,iph->ihl);
+
+ netlink_packet_deliver(st,buf);
+ BUF_ASSERT_FREE(buf);
+}
+
+/* Someone has been foolish enough to address a packet to us. I
+ suppose we should reply to it, just to be polite. */
+static void netlink_packet_local(struct netlink *st, struct buffer_if *buf)
+{
+ struct icmphdr *h;
+
+ h=(struct icmphdr *)buf->start;
+
+ if ((ntohs(h->iph.frag_off)&0xbfff)!=0) {
+ Message(M_WARNING,"%s: fragmented packet addressed to us\n",st->name);
+ BUF_FREE(buf);
+ return;
+ }
+
+ if (h->iph.protocol==1) {
+ /* It's ICMP */
+ if (h->type==8 && h->code==0) {
+ /* ICMP echo-request. Special case: we re-use the buffer
+ to construct the reply. */
+ h->type=0;
+ 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.check=0;
+ h->iph.check=ip_fast_csum((uint8_t *)h,h->iph.ihl);
+ netlink_icmp_csum(h);
+ netlink_packet_deliver(st,buf);
+ return;
+ }
+ Message(M_WARNING,"%s: unknown incoming ICMP\n",st->name);
+ } else {
+ /* Send ICMP protocol unreachable */
+ netlink_icmp_simple(st,buf,3,2);
+ BUF_FREE(buf);
+ return;
+ }
+
+ BUF_FREE(buf);
+}
+
+/* Called by site code when remote packet is available */
+/* buf is allocated on entry and free on return */
+static void netlink_from_tunnel(void *sst, void *cst, struct buffer_if *buf)
+{
+ struct netlink *st=sst;
+ struct netlink_client *client=cst;
+ uint32_t source,dest;
+ struct iphdr *iph;
+
+ BUF_ASSERT_USED(buf);
+ if (!netlink_check(st,buf)) {
+ Message(M_WARNING,"%s: bad IP packet from tunnel %s\n",
+ st->name,client->name);
+ BUF_FREE(buf);
+ return;
+ }
+ iph=(struct iphdr *)buf->start;
+
+ source=ntohl(iph->saddr);
+ dest=ntohl(iph->daddr);
+
+ /* Check that the packet source is in 'nets' and its destination is
+ in client->networks */
+ if (!subnet_match(client->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);
+ BUF_FREE(buf);
+ return;
+ }
+ /* (st->secnet_address needs checking before matching against
+ st->networks because secnet's IP address may not be in the
+ range the host is willing to deal with) */
if (dest==st->secnet_address) {
- printf("%s: secnet received packet of len %d from %s\n",st->name,
- st->buff->size,ipaddr_to_string(source));
+ netlink_packet_local(st,buf);
+ BUF_ASSERT_FREE(buf);
return;
}
- {
+ if (!subnet_match(&st->networks,dest)) {
string_t s,d;
s=ipaddr_to_string(source);
d=ipaddr_to_string(dest);
- Message(M_WARNING,"%s: outgoing packet with bad destination address "
- "(s=%s,d=%s)\n",st->name,s,d);
+ Message(M_WARNING,"%s: incoming packet from tunnel %s "
+ "with bad destination address "
+ "(s=%s,d=%s)\n",st->name,client->name,s,d);
free(s); free(d);
+ BUF_FREE(buf);
return;
}
+
+ netlink_packet_forward(st,buf);
+
+ BUF_ASSERT_FREE(buf);
+}
+
+/* Called by driver code when packet is received from kernel */
+/* cid should be NULL */
+/* buf should be allocated on entry, and is free on return */
+static void netlink_from_host(void *sst, void *cid, struct buffer_if *buf)
+{
+ struct netlink *st=sst;
+ uint32_t source,dest;
+ struct iphdr *iph;
+
+ BUF_ASSERT_USED(buf);
+ if (!netlink_check(st,buf)) {
+ Message(M_WARNING,"%s: bad IP packet from host\n",
+ st->name);
+ BUF_FREE(buf);
+ return;
+ }
+ iph=(struct iphdr *)buf->start;
+
+ source=ntohl(iph->saddr);
+ dest=ntohl(iph->daddr);
+
+ if (!subnet_match(&st->networks,source)) {
+ string_t s,d;
+ s=ipaddr_to_string(source);
+ 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 (dest==st->secnet_address) {
+ netlink_packet_local(st,buf);
+ BUF_ASSERT_FREE(buf);
+ return;
+ }
+ netlink_packet_forward(st,buf);
+ BUF_ASSERT_FREE(buf);
+}
+
+static void netlink_set_delivery(void *sst, void *cid, bool_t can_deliver)
+{
+ struct netlink_client *c=cid;
+
+ c->can_deliver=can_deliver;
+}
+
+static void *netlink_regnets(void *sst, struct subnet_list *nets,
+ netlink_deliver_fn *deliver, void *dst,
+ uint32_t max_start_pad, uint32_t max_end_pad,
+ string_t client_name)
+{
+ struct netlink *st=sst;
+ struct netlink_client *c;
+
+ Message(M_DEBUG_CONFIG,"netlink_regnets: request for %d networks, "
+ "max_start_pad=%d, max_end_pad=%d\n",
+ nets->entries,max_start_pad,max_end_pad);
+
+ c=safe_malloc(sizeof(*c),"netlink_regnets");
+ c->networks=nets;
+ c->deliver=deliver;
+ c->dst=dst;
+ c->name=client_name; /* XXX copy it? */
+ c->can_deliver=False;
+ c->next=st->clients;
+ st->clients=c;
+ 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;
+
+ return c;
+}
+
+static netlink_deliver_fn *netlink_init(struct netlink *st,
+ void *dst, struct cloc loc,
+ dict_t *dict, string_t description,
+ netlink_deliver_fn *to_host)
+{
+ st->dst=dst;
+ st->cl.description=description;
+ st->cl.type=CL_NETLINK;
+ st->cl.apply=NULL;
+ st->cl.interface=&st->ops;
+ st->ops.st=st;
+ st->ops.regnets=netlink_regnets;
+ st->ops.deliver=netlink_from_tunnel;
+ st->ops.set_delivery=netlink_set_delivery;
+ st->max_start_pad=0;
+ st->max_end_pad=0;
+ st->clients=NULL;
+ st->deliver_to_host=to_host;
+
+ st->name=dict_read_string(dict,"name",False,"netlink",loc);
+ if (!st->name) st->name=description;
+ dict_read_subnet_list(dict, "networks", True, "netlink", loc,
+ &st->networks);
+ st->local_address=string_to_ipaddr(
+ dict_find_item(dict,"local-address", True, "netlink", loc),"netlink");
+ st->secnet_address=string_to_ipaddr(
+ dict_find_item(dict,"secnet-address", True, "netlink", loc),"netlink");
+ if (!subnet_match(&st->networks,st->local_address)) {
+ cfgfatal(loc,"netlink","local-address must be in local networks\n");
+ }
+ st->mtu=dict_read_number(dict, "mtu", False, "netlink", loc, DEFAULT_MTU);
+ buffer_new(&st->icmp,ICMP_BUFSIZE);
+
+ return netlink_from_host;
+}
+
+/* Connection to the kernel through userv-ipif */
+
+struct userv {
+ struct netlink nl;
+ int txfd; /* We transmit to userv */
+ int rxfd; /* We receive from userv */
+ string_t userv_path;
+ string_t service_user;
+ string_t service_name;
+ uint32_t txbuflen;
+ struct buffer_if *buff; /* We unstuff received packets into here
+ and send them to the site code. */
+ bool_t pending_esc;
+ netlink_deliver_fn *netlink_to_tunnel;
+};
+
+static int userv_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
+ int *timeout_io, const struct timeval *tv_now,
+ uint64_t *now)
+{
+ struct userv *st=sst;
+ *nfds_io=2;
+ fds[0].fd=st->txfd;
+ fds[0].events=POLLERR; /* Might want to pick up POLLOUT sometime */
+ fds[1].fd=st->rxfd;
+ fds[1].events=POLLIN|POLLERR|POLLHUP;
+ return 0;
}
static void userv_afterpoll(void *sst, struct pollfd *fds, int nfds,
}
/* XXX really crude unstuff code */
/* XXX check for buffer overflow */
+ BUF_ASSERT_USED(st->buff);
for (i=0; i<l; i++) {
if (st->pending_esc) {
st->pending_esc=False;
} else {
switch (rxbuf[i]) {
case SLIP_END:
- if (st->buff->size>0) process_local_packet(st);
- BUF_ASSERT_USED(st->buff);
- buffer_init(st->buff,st->max_start_pad);
+ if (st->buff->size>0) {
+ st->netlink_to_tunnel(&st->nl,NULL,
+ st->buff);
+ BUF_ALLOC(st->buff,"userv_afterpoll");
+ }
+ buffer_init(st->buff,st->nl.max_start_pad);
break;
case SLIP_ESC:
st->pending_esc=True;
}
}
}
- return;
+}
+
+/* Send buf to the kernel. Free buf before returning. */
+static void userv_deliver_to_kernel(void *sst, void *cid,
+ struct buffer_if *buf)
+{
+ struct userv *st=sst;
+ uint8_t txbuf[DEFAULT_BUFSIZE];
+ uint8_t *i;
+ uint32_t j;
+
+ BUF_ASSERT_USED(buf);
+
+ /* Spit the packet at userv-ipif: SLIP start marker, then
+ bytestuff the packet, then SLIP end marker */
+ /* XXX crunchy bytestuff code */
+ j=0;
+ txbuf[j++]=SLIP_END;
+ for (i=buf->start; i<(buf->start+buf->size); i++) {
+ switch (*i) {
+ case SLIP_END:
+ txbuf[j++]=SLIP_ESC;
+ txbuf[j++]=SLIP_ESCEND;
+ break;
+ case SLIP_ESC:
+ txbuf[j++]=SLIP_ESC;
+ txbuf[j++]=SLIP_ESCESC;
+ break;
+ default:
+ txbuf[j++]=*i;
+ break;
+ }
+ }
+ txbuf[j++]=SLIP_END;
+ if (write(st->txfd,txbuf,j)<0) {
+ fatal_perror("userv_deliver_to_kernel: write()");
+ }
+ BUF_FREE(buf);
}
static void userv_phase_hook(void *sst, uint32_t newphase)
be using should already have been registered. */
addrs=safe_malloc(512,"userv_phase_hook:addrs");
- snprintf(addrs,512,"%s,%s,%d,slip",ipaddr_to_string(st->local_address),
- ipaddr_to_string(st->secnet_address),st->mtu);
+ snprintf(addrs,512,"%s,%s,%d,slip",ipaddr_to_string(st->nl.local_address),
+ ipaddr_to_string(st->nl.secnet_address),st->nl.mtu);
nets=safe_malloc(1024,"userv_phase_hook:nets");
*nets=0;
- for (c=st->clients; c; c=c->next) {
+ for (c=st->nl.clients; c; c=c->next) {
for (i=0; i<c->networks->entries; i++) {
s=subnet_to_string(&c->networks->list[i]);
strcat(nets,s);
/* We are the parent... */
/* Register for poll() */
- register_for_poll(st, userv_beforepoll, userv_afterpoll, 2, "netlink");
+ register_for_poll(st, userv_beforepoll, userv_afterpoll, 2, st->nl.name);
}
-static void *userv_regnets(void *sst, struct subnet_list *nets,
- netlink_deliver_fn *deliver, void *dst,
- uint32_t max_start_pad, uint32_t max_end_pad)
+static list_t *userv_apply(closure_t *self, struct cloc loc, dict_t *context,
+ list_t *args)
{
- struct userv *st=sst;
- struct netlink_client *c;
+ struct userv *st;
+ item_t *item;
+ dict_t *dict;
- Message(M_DEBUG_CONFIG,"userv_regnets: request for %d networks, "
- "max_start_pad=%d, max_end_pad=%d\n",
- nets->entries,max_start_pad,max_end_pad);
+ st=safe_malloc(sizeof(*st),"userv_apply");
- c=safe_malloc(sizeof(*c),"userv_regnets");
- c->networks=nets;
- c->deliver=deliver;
- c->dst=dst;
- c->next=st->clients;
- st->clients=c;
- 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;
+ /* First parameter must be a dict */
+ item=list_elem(args,0);
+ if (!item || item->type!=t_dict)
+ cfgfatal(loc,"userv-ipif","parameter must be a dictionary\n");
+
+ dict=item->data.dict;
- return c;
+ st->netlink_to_tunnel=
+ netlink_init(&st->nl,st,loc,dict,
+ "netlink-userv-ipif",userv_deliver_to_kernel);
+
+ st->userv_path=dict_read_string(dict,"userv-path",False,"userv-netlink",
+ loc);
+ st->service_user=dict_read_string(dict,"service-user",False,
+ "userv-netlink",loc);
+ st->service_name=dict_read_string(dict,"service-name",False,
+ "userv-netlink",loc);
+ if (!st->userv_path) st->userv_path="userv";
+ if (!st->service_user) st->service_user="root";
+ if (!st->service_name) st->service_name="ipif";
+ st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"userv-netlink",loc);
+ BUF_ALLOC(st->buff,"netlink:userv_apply");
+
+ st->rxfd=-1; st->txfd=-1;
+ add_hook(PHASE_DROPPRIV,userv_phase_hook,st);
+
+ return new_closure(&st->nl.cl);
}
-static void userv_deliver(void *sst, void *cid, struct buffer_if *buf)
-{
- struct userv *st=sst;
- struct netlink_client *client=cid;
- uint8_t txbuf[DEFAULT_BUFSIZE];
+/* Connection to the kernel through the universal TUN/TAP driver */
- uint32_t source,dest;
- uint8_t *i;
- uint32_t j;
+struct tun {
+ struct netlink nl;
+ int fd;
+ string_t device_path;
+ string_t interface_name;
+ string_t ifconfig_path;
+ string_t route_path;
+ struct buffer_if *buff; /* We receive packets into here
+ and send them to the netlink code. */
+ netlink_deliver_fn *netlink_to_tunnel;
+};
- source=ntohl(*(uint32_t *)(buf->start+12));
- dest=ntohl(*(uint32_t *)(buf->start+16));
+static int tun_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
+ int *timeout_io, const struct timeval *tv_now,
+ uint64_t *now)
+{
+ struct tun *st=sst;
+ *nfds_io=1;
+ fds[0].fd=st->fd;
+ fds[0].events=POLLIN|POLLERR|POLLHUP;
+ return 0;
+}
- /* Check that the packet source is in 'nets' and its destination is
- in client->networks */
- if (!subnet_match(client->networks,source)) {
- string_t s,d;
- s=ipaddr_to_string(source);
- d=ipaddr_to_string(dest);
- Message(M_WARNING,"%s: incoming packet with bad source address "
- "(s=%s,d=%s)\n",st->name,s,d);
- free(s); free(d);
- return;
+static void tun_afterpoll(void *sst, struct pollfd *fds, int nfds,
+ const struct timeval *tv_now, uint64_t *now)
+{
+ struct tun *st=sst;
+ int l;
+
+ if (fds[0].revents&POLLERR) {
+ printf("tun_afterpoll: hup!\n");
}
- if (!subnet_match(&st->networks,dest)) {
- string_t s,d;
- s=ipaddr_to_string(source);
- d=ipaddr_to_string(dest);
- Message(M_WARNING,"%s: incoming packet with bad destination address "
- "(s=%s,d=%s)\n",st->name,s,d);
- free(s); free(d);
- return;
+ if (fds[0].revents&POLLIN) {
+ BUF_ALLOC(st->buff,"tun_afterpoll");
+ buffer_init(st->buff,st->nl.max_start_pad);
+ l=read(st->fd,st->buff->start,st->buff->len-st->nl.max_start_pad);
+ if (l<0) {
+ fatal_perror("tun_afterpoll: read()");
+ }
+ if (l==0) {
+ fatal("tun_afterpoll: read()=0; device gone away?\n");
+ }
+ if (l>0) {
+ st->buff->size=l;
+ st->netlink_to_tunnel(&st->nl,NULL,st->buff);
+ BUF_ASSERT_FREE(st->buff);
+ }
}
+}
- /* Really we should decrease TTL, check it's above zero, and
- recalculate header checksum here. If it gets down to zero,
- generate an ICMP time-exceeded and send the new packet back to
- the originating tunnel. XXX check buffer usage! */
+static void tun_deliver_to_kernel(void *sst, void *cid,
+ struct buffer_if *buf)
+{
+ struct tun *st=sst;
- /* (Basically do full IP packet forwarding stuff. Except that we
- know any packet passed in here is destined for the local
- machine; only exception is if it's destined for us.) */
+ BUF_ASSERT_USED(buf);
- if (dest==st->secnet_address) {
- printf("%s: incoming tunneled packet for secnet!\n",st->name);
- return;
- }
+ /* No error checking, because we'd just throw the packet away anyway */
+ write(st->fd,buf->start,buf->size);
+ BUF_FREE(buf);
+}
- /* Now spit the packet at userv-ipif: SLIP start marker, then
- bytestuff the packet, then SLIP end marker */
- /* XXX crunchy bytestuff code */
- j=0;
- txbuf[j++]=SLIP_END;
- for (i=buf->start; i<(buf->start+buf->size); i++) {
- switch (*i) {
- case SLIP_END:
- txbuf[j++]=SLIP_ESC;
- txbuf[j++]=SLIP_ESCEND;
- break;
- case SLIP_ESC:
- txbuf[j++]=SLIP_ESC;
- txbuf[j++]=SLIP_ESCESC;
- break;
- default:
- txbuf[j++]=*i;
- break;
+static void tun_phase_hook(void *sst, uint32_t newphase)
+{
+ struct tun *st=sst;
+ string_t hostaddr,secnetaddr;
+ uint8_t mtu[6];
+ string_t network,mask;
+ struct netlink_client *c;
+ int i;
+
+ /* All the networks we'll be using have been registered. Invoke ifconfig
+ to set the TUN device's address, and route to add routes to all
+ our networks. */
+
+ hostaddr=ipaddr_to_string(st->nl.local_address);
+ secnetaddr=ipaddr_to_string(st->nl.secnet_address);
+ snprintf(mtu,6,"%d",st->nl.mtu);
+ mtu[5]=0;
+
+ sys_cmd(st->ifconfig_path,"ifconfig",st->interface_name,
+ hostaddr,"netmask","255.255.255.255","-broadcast",
+ "pointopoint",secnetaddr,"mtu",mtu,"up",(char *)0);
+
+ for (c=st->nl.clients; c; c=c->next) {
+ for (i=0; i<c->networks->entries; i++) {
+ network=ipaddr_to_string(c->networks->list[i].prefix);
+ mask=ipaddr_to_string(c->networks->list[i].mask);
+ sys_cmd(st->route_path,"route","add","-net",network,
+ "netmask",mask,"gw",secnetaddr,(char *)0);
}
}
- txbuf[j++]=SLIP_END;
- if (write(st->txfd,txbuf,j)<0) {
- fatal_perror("userv_deliver: write()");
+
+ /* Register for poll() */
+ register_for_poll(st, tun_beforepoll, tun_afterpoll, 1, st->nl.name);
+}
+
+#ifdef HAVE_LINUX_IF_H
+static list_t *tun_apply(closure_t *self, struct cloc loc, dict_t *context,
+ list_t *args)
+{
+ struct tun *st;
+ item_t *item;
+ dict_t *dict;
+ struct ifreq ifr;
+
+ st=safe_malloc(sizeof(*st),"tun_apply");
+
+ /* First parameter must be a dict */
+ item=list_elem(args,0);
+ if (!item || item->type!=t_dict)
+ cfgfatal(loc,"tun","parameter must be a dictionary\n");
+
+ dict=item->data.dict;
+
+ st->netlink_to_tunnel=
+ netlink_init(&st->nl,st,loc,dict,
+ "netlink-tun",tun_deliver_to_kernel);
+
+ st->device_path=dict_read_string(dict,"device",False,"tun-netlink",loc);
+ st->interface_name=dict_read_string(dict,"interface",False,
+ "tun-netlink",loc);
+ st->ifconfig_path=dict_read_string(dict,"device",False,"tun-netlink",loc);
+ st->route_path=dict_read_string(dict,"device",False,"tun-netlink",loc);
+
+ if (!st->device_path) st->device_path="/dev/net/tun";
+ if (!st->ifconfig_path) st->ifconfig_path="ifconfig";
+ if (!st->route_path) st->route_path="route";
+ st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"tun-netlink",loc);
+
+ /* New TUN interface: open the device, then do ioctl TUNSETIFF
+ to set or find out the network interface name. */
+ st->fd=open(st->device_path,O_RDWR);
+ if (st->fd==-1) {
+ fatal_perror("%s: can't open device file %s",st->nl.name,
+ st->device_path);
+ }
+ memset(&ifr,0,sizeof(ifr));
+ ifr.ifr_flags = IFF_TUN | IFF_NO_PI; /* Just send/receive IP packets,
+ no extra headers */
+ if (st->interface_name)
+ strncpy(ifr.ifr_name,st->interface_name,IFNAMSIZ);
+ if (ioctl(st->fd,TUNSETIFF,&ifr)<0) {
+ fatal_perror("%s: ioctl(TUNSETIFF)",st->nl.name);
+ }
+ if (!st->interface_name) {
+ st->interface_name=safe_malloc(strlen(ifr.ifr_name)+1,"tun_apply");
+ strcpy(st->interface_name,ifr.ifr_name);
+ Message(M_INFO,"%s: allocated network interface %s\n",st->nl.name,
+ st->interface_name);
}
- return;
+ add_hook(PHASE_DROPPRIV,tun_phase_hook,st);
+
+ return new_closure(&st->nl.cl);
}
+#endif /* HAVE_LINUX_IF_H */
-static list_t *userv_apply(closure_t *self, struct cloc loc, dict_t *context,
- list_t *args)
+static list_t *tun_old_apply(closure_t *self, struct cloc loc, dict_t *context,
+ list_t *args)
{
- struct userv *st;
+ struct tun *st;
item_t *item;
dict_t *dict;
+ bool_t search_for_if;
- st=safe_malloc(sizeof(*st),"userv_apply (netlink)");
- st->cl.description="userv-netlink";
- st->cl.type=CL_NETLINK;
- st->cl.apply=NULL;
- st->cl.interface=&st->ops;
- st->ops.st=st;
- st->ops.regnets=userv_regnets;
- st->ops.deliver=userv_deliver;
- st->max_start_pad=0;
- st->max_end_pad=0;
- st->rxfd=-1; st->txfd=-1;
- st->clients=NULL;
+ st=safe_malloc(sizeof(*st),"tun_old_apply");
+
+ Message(M_WARNING,"the tun-old code has never been tested. Please report "
+ "success or failure to steve@greenend.org.uk\n");
/* First parameter must be a dict */
item=list_elem(args,0);
if (!item || item->type!=t_dict)
- cfgfatal(loc,"userv-ipif","parameter must be a dictionary\n");
+ cfgfatal(loc,"tun","parameter must be a dictionary\n");
dict=item->data.dict;
- st->name=dict_read_string(dict,"name",False,"userv-netlink",loc);
- st->userv_path=dict_read_string(dict,"userv-path",False,"userv-netlink",
- loc);
- st->service_user=dict_read_string(dict,"service-user",False,
- "userv-netlink",loc);
- st->service_name=dict_read_string(dict,"service-name",False,
- "userv-netlink",loc);
- if (!st->name) st->name="netlink-userv-ipif";
- if (!st->userv_path) st->userv_path="userv";
- if (!st->service_user) st->service_user="root";
- if (!st->service_name) st->service_name="ipif";
- dict_read_subnet_list(dict, "networks", True, "userv-netlink", loc,
- &st->networks);
- st->local_address=string_to_ipaddr(
- dict_find_item(dict,"local-address", True, "userv-netlink", loc),
- "userv-netlink");
- st->secnet_address=string_to_ipaddr(
- dict_find_item(dict,"secnet-address", True, "userv-netlink", loc),
- "userv-netlink");
- if (!subnet_match(&st->networks,st->local_address)) {
- cfgfatal(loc,"netlink-userv-ipif","local-address must be in "
- "local networks\n");
+
+ st->netlink_to_tunnel=
+ netlink_init(&st->nl,st,loc,dict,
+ "netlink-tun",tun_deliver_to_kernel);
+
+ st->device_path=dict_read_string(dict,"device",False,"tun-netlink",loc);
+ st->interface_name=dict_read_string(dict,"interface",False,
+ "tun-netlink",loc);
+ search_for_if=dict_read_bool(dict,"interface-search",False,"tun-netlink",
+ loc,st->device_path==NULL);
+ st->ifconfig_path=dict_read_string(dict,"device",False,"tun-netlink",loc);
+ st->route_path=dict_read_string(dict,"device",False,"tun-netlink",loc);
+
+ if (!st->device_path) st->device_path="/dev/tun";
+ if (!st->ifconfig_path) st->ifconfig_path="ifconfig";
+ if (!st->route_path) st->route_path="route";
+ st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"tun-netlink",loc);
+
+ /* Old TUN interface: the network interface name depends on which
+ /dev/tunX file we open. If 'interface-search' is set to true, treat
+ 'device' as the prefix and try numbers from 0--255. If it's set
+ to false, treat 'device' as the whole name, and require than an
+ appropriate interface name be specified. */
+ if (search_for_if) {
+ string_t dname;
+ int i;
+
+ if (st->interface_name) {
+ cfgfatal(loc,"tun-old","you may not specify an interface name "
+ "in interface-search mode\n");
+ }
+ dname=safe_malloc(strlen(st->device_path)+4,"tun_old_apply");
+ st->interface_name=safe_malloc(8,"tun_old_apply");
+
+ for (i=0; i<255; i++) {
+ sprintf(dname,"%s%d",st->device_path,i);
+ if ((st->fd=open(dname,O_RDWR))>0) {
+ sprintf(st->interface_name,"tun%d",i);
+ Message(M_INFO,"%s: allocated network interface %s "
+ "through %s\n",st->nl.name,st->interface_name,dname);
+ continue;
+ }
+ }
+ if (st->fd==-1) {
+ fatal("%s: unable to open any TUN device (%s...)\n",
+ st->nl.name,st->device_path);
+ }
+ } else {
+ if (!st->interface_name) {
+ cfgfatal(loc,"tun-old","you must specify an interface name "
+ "when you explicitly specify a TUN device file\n");
+ }
+ st->fd=open(st->device_path,O_RDWR);
+ if (st->fd==-1) {
+ fatal_perror("%s: unable to open TUN device file %s",
+ st->nl.name,st->device_path);
+ }
}
- st->mtu=dict_read_number(dict, "mtu", False, "userv-netlink", loc, 1000);
- st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"userv-netlink",loc);
- BUF_ALLOC(st->buff,"netlink:userv_apply");
- add_hook(PHASE_DROPPRIV,userv_phase_hook,st);
+ add_hook(PHASE_DROPPRIV,tun_phase_hook,st);
- return new_closure(&st->cl);
+ return new_closure(&st->nl.cl);
}
+/* No connection to the kernel at all... */
+
struct null {
- closure_t cl;
- struct netlink_if ops;
+ struct netlink nl;
};
-static void *null_regnets(void *sst, struct subnet_list *nets,
- netlink_deliver_fn *deliver, void *dst,
- uint32_t max_start_pad, uint32_t max_end_pad)
-{
- Message(M_DEBUG_CONFIG,"null_regnets: request for %d networks, "
- "max_start_pad=%d, max_end_pad=%d\n",
- nets->entries,max_start_pad,max_end_pad);
- return NULL;
-}
-
static void null_deliver(void *sst, void *cid, struct buffer_if *buf)
{
return;
list_t *args)
{
struct null *st;
+ item_t *item;
+ dict_t *dict;
- st=safe_malloc(sizeof(*st),"null_apply (netlink)");
- st->cl.description="null-netlink";
- st->cl.type=CL_NETLINK;
- st->cl.apply=NULL;
- st->cl.interface=&st->ops;
- st->ops.st=st;
- st->ops.regnets=null_regnets;
- st->ops.deliver=null_deliver;
+ st=safe_malloc(sizeof(*st),"null_apply");
- return new_closure(&st->cl);
+ item=list_elem(args,0);
+ if (!item || item->type!=t_dict)
+ cfgfatal(loc,"null-netlink","parameter must be a dictionary\n");
+
+ dict=item->data.dict;
+
+ netlink_init(&st->nl,st,loc,dict,"null-netlink",null_deliver);
+
+ return new_closure(&st->nl.cl);
}
init_module netlink_module;
void netlink_module(dict_t *dict)
{
add_closure(dict,"userv-ipif",userv_apply);
+#ifdef HAVE_LINUX_IF_H
+ add_closure(dict,"tun",tun_apply);
+#endif
+ add_closure(dict,"tun-old",tun_old_apply);
+ add_closure(dict,"null-netlink",null_apply);
#if 0
+ /* TODO */
add_closure(dict,"pty-slip",ptyslip_apply);
add_closure(dict,"slipd",slipd_apply);
#endif /* 0 */
- add_closure(dict,"null-netlink",null_apply);
}
~ian / secnet.git / blobdiff