pppd: Add defaultroute6 and related options

Which behave like IPv4's defaultroute etc.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

pppd/ipv6cp.c

@@ -177,6 +177,7 @@ ipv6cp_options ipv6cp_hisoptions[NUM_PPP];	/* Options that we ack'd */
 int no_ifaceid_neg = 0;
 
 /* local vars */
+static int default_route_set[NUM_PPP];		/* Have set up a default route */
 static int ipv6cp_is_up;
 
 /* Hook for a plugin to know when IPv6 protocol has come up */
@@ -245,6 +246,15 @@ static option_t ipv6cp_option_list[] = {
     { "ipv6cp-accept-local", o_bool, &ipv6cp_allowoptions[0].accept_local,
       "Accept peer's interface identifier for us", 1 },
 
+    { "defaultroute6", o_bool, &ipv6cp_wantoptions[0].default_route,
+      "Add default IPv6 route", OPT_ENABLE|1, &ipv6cp_allowoptions[0].default_route },
+    { "nodefaultroute6", o_bool, &ipv6cp_allowoptions[0].default_route,
+      "disable defaultroute6 option", OPT_A2CLR,
+      &ipv6cp_wantoptions[0].default_route },
+    { "-defaultroute6", o_bool, &ipv6cp_allowoptions[0].default_route,
+      "disable defaultroute6 option", OPT_ALIAS | OPT_A2CLR,
+      &ipv6cp_wantoptions[0].default_route },
+
     { "ipv6cp-use-ipaddr", o_bool, &ipv6cp_allowoptions[0].use_ip,
       "Use (default) IPv4 address as interface identifier", 1 },
 
@@ -443,6 +453,10 @@ ipv6cp_init(unit)
     wo->vj_protocol = IPV6CP_COMP;
 #endif
 
+    /*
+     * XXX This controls whether the user may use the defaultroute option.
+     */
+    ao->default_route = 1;
 }
 
 
@@ -1151,6 +1165,9 @@ ipv6_demand_conf(u)
 #endif
     if (!sifnpmode(u, PPP_IPV6, NPMODE_QUEUE))
 	return 0;
+    if (wo->default_route)
+	if (sif6defaultroute(u, wo->ourid, wo->hisid))
+	    default_route_set[u] = 1;
 
     notice("ipv6_demand_conf");
     notice("local  LL address %s", llv6_ntoa(wo->ourid));
@@ -1230,6 +1247,10 @@ ipv6cp_up(f)
 		return;
 	    }
 
+	    /* assign a default route through the interface if required */
+	    if (ipv6cp_wantoptions[f->unit].default_route)
+		if (sif6defaultroute(f->unit, go->ourid, ho->hisid))
+		    default_route_set[f->unit] = 1;
 	}
 	demand_rexmit(PPP_IPV6);
 	sifnpmode(f->unit, PPP_IPV6, NPMODE_PASS);
@@ -1251,6 +1272,11 @@ ipv6cp_up(f)
 	}
 	sifnpmode(f->unit, PPP_IPV6, NPMODE_PASS);
 
+	/* assign a default route through the interface if required */
+	if (ipv6cp_wantoptions[f->unit].default_route)
+	    if (sif6defaultroute(f->unit, go->ourid, ho->hisid))
+		default_route_set[f->unit] = 1;
+
 	notice("local  LL address %s", llv6_ntoa(go->ourid));
 	notice("remote LL address %s", llv6_ntoa(ho->hisid));
     }

pppd/ipv6cp.h

@@ -150,6 +150,7 @@
 typedef struct ipv6cp_options {
     int neg_ifaceid;		/* Negotiate interface identifier? */
     int req_ifaceid;		/* Ask peer to send interface identifier? */
+    int default_route;		/* Assign default route through interface? */
     int accept_local;		/* accept peer's value for iface id? */
     int opt_local;		/* ourtoken set by option */
     int opt_remote;		/* histoken set by option */

pppd/pppd.8

@@ -127,6 +127,12 @@ is no other default route with the same metric.  With the default
 value of -1, the route is only added if there is no default route at
 all.
 .TP
+.B defaultroute6
+Add a default IPv6 route to the system routing tables, using the peer as
+the gateway, when IPv6CP negotiation is successfully completed.
+This entry is removed when the PPP connection is broken.  This option
+is privileged if the \fInodefaultroute6\fR option has been specified.
+.TP
 .B disconnect \fIscript
 Execute the command specified by \fIscript\fR, by passing it to a
 shell, after
@@ -743,6 +749,11 @@ Disable the \fIdefaultroute\fR option.  The system administrator who
 wishes to prevent users from creating default routes with pppd
 can do so by placing this option in the /etc/ppp/options file.
 .TP
+.B nodefaultroute6
+Disable the \fIdefaultroute6\fR option.  The system administrator who
+wishes to prevent users from adding a default route with pppd
+can do so by placing this option in the /etc/ppp/options file.
+.TP
 .B nodeflate
 Disables Deflate compression; pppd will not request or agree to
 compress packets using the Deflate scheme.

pppd/pppd.h

@@ -683,6 +683,12 @@ int  sifdefaultroute __P((int, u_int32_t, u_int32_t));
 				/* Create default route through i/f */
 int  cifdefaultroute __P((int, u_int32_t, u_int32_t));
 				/* Delete default route through i/f */
+#ifdef INET6
+int  sif6defaultroute __P((int, eui64_t, eui64_t));
+				/* Create default IPv6 route through i/f */
+int  cif6defaultroute __P((int, eui64_t, eui64_t));
+				/* Delete default IPv6 route through i/f */
+#endif
 int  sifproxyarp __P((int, u_int32_t));
 				/* Add proxy ARP entry for peer */
 int  cifproxyarp __P((int, u_int32_t));

pppd/sys-linux.c

@@ -163,6 +163,7 @@ struct in6_ifreq {
 	eui64_copy(eui64, sin6.s6_addr32[2]);			\
 	} while (0)
 
+static const eui64_t nulleui64;
 #endif /* INET6 */
 
 /* We can get an EIO error on an ioctl if the modem has hung up */
@@ -207,6 +208,7 @@ static unsigned char inbuf[512]; /* buffer for chars read from loopback */
 static int	if_is_up;	/* Interface has been marked up */
 static int	if6_is_up;	/* Interface has been marked up for IPv6, to help differentiate */
 static int	have_default_route;	/* Gateway for default route added */
+static int	have_default_route6;	/* Gateway for default IPv6 route added */
 static u_int32_t proxy_arp_addr;	/* Addr for proxy arp entry added */
 static char proxy_arp_dev[16];		/* Device for proxy arp entry */
 static u_int32_t our_old_addr;		/* for detecting address changes */
@@ -234,6 +236,7 @@ static void close_route_table (void);
 static int open_route_table (void);
 static int read_route_table (struct rtentry *rt);
 static int defaultroute_exists (struct rtentry *rt, int metric);
+static int defaultroute6_exists (struct in6_rtmsg *rt, int metric);
 static int get_ether_addr (u_int32_t ipaddr, struct sockaddr *hwaddr,
 			   char *name, int namelen);
 static void decode_version (char *buf, int *version, int *mod, int *patch);
@@ -350,6 +353,10 @@ void sys_cleanup(void)
  */
     if (have_default_route)
 	cifdefaultroute(0, 0, 0);
+#ifdef INET6
+    if (have_default_route6)
+	cif6defaultroute(0, nulleui64, nulleui64);
+#endif
 
     if (has_proxy_arp)
 	cifproxyarp(0, proxy_arp_addr);
@@ -1710,6 +1717,198 @@ int cifdefaultroute (int unit, u_int32_t ouraddr, u_int32_t gateway)
     return 1;
 }
 
+#ifdef INET6
+/*
+ * /proc/net/ipv6_route parsing stuff.
+ */
+static int route_dest_plen_col;
+static int open_route6_table (void);
+static int read_route6_table (struct in6_rtmsg *rt);
+
+/********************************************************************
+ *
+ * open_route6_table - open the interface to the route table
+ */
+static int open_route6_table (void)
+{
+    char *path;
+
+    close_route_table();
+
+    path = path_to_procfs("/net/ipv6_route");
+    route_fd = fopen (path, "r");
+    if (route_fd == NULL) {
+	error("can't open routing table %s: %m", path);
+	return 0;
+    }
+
+    /* default to usual columns */
+    route_dest_col = 0;
+    route_dest_plen_col = 1;
+    route_gw_col = 4;
+    route_metric_col = 5;
+    route_flags_col = 8;
+    route_dev_col = 9;
+    route_num_cols = 10;
+
+    return 1;
+}
+
+/********************************************************************
+ *
+ * read_route6_table - read the next entry from the route table
+ */
+
+static void hex_to_in6_addr(struct in6_addr *addr, const char *s)
+{
+    char hex8[9];
+    unsigned i;
+    uint32_t v;
+
+    hex8[8] = 0;
+    for (i = 0; i < 4; i++) {
+	memcpy(hex8, s + 8*i, 8);
+	v = strtoul(hex8, NULL, 16);
+	addr->s6_addr32[i] = v;
+    }
+}
+
+static int read_route6_table(struct in6_rtmsg *rt)
+{
+    char *cols[ROUTE_MAX_COLS], *p;
+    int col;
+
+    memset (rt, '\0', sizeof (struct in6_rtmsg));
+
+    if (fgets (route_buffer, sizeof (route_buffer), route_fd) == (char *) 0)
+	return 0;
+
+    p = route_buffer;
+    for (col = 0; col < route_num_cols; ++col) {
+	cols[col] = strtok(p, route_delims);
+	if (cols[col] == NULL)
+	    return 0;		/* didn't get enough columns */
+	p = NULL;
+    }
+
+    hex_to_in6_addr(&rt->rtmsg_dst, cols[route_dest_col]);
+    rt->rtmsg_dst_len = strtoul(cols[route_dest_plen_col], NULL, 16);
+    hex_to_in6_addr(&rt->rtmsg_gateway, cols[route_gw_col]);
+
+    rt->rtmsg_metric = strtoul(cols[route_metric_col], NULL, 16);
+    rt->rtmsg_flags = strtoul(cols[route_flags_col], NULL, 16);
+    rt->rtmsg_ifindex = if_nametoindex(cols[route_dev_col]);
+
+    return 1;
+}
+
+/********************************************************************
+ *
+ * defaultroute6_exists - determine if there is a default route
+ */
+
+static int defaultroute6_exists (struct in6_rtmsg *rt, int metric)
+{
+    int result = 0;
+
+    if (!open_route6_table())
+	return 0;
+
+    while (read_route6_table(rt) != 0) {
+	if ((rt->rtmsg_flags & RTF_UP) == 0)
+	    continue;
+
+	if (rt->rtmsg_dst_len != 0)
+	    continue;
+	if (rt->rtmsg_dst.s6_addr32[0] == 0L
+	 && rt->rtmsg_dst.s6_addr32[1] == 0L
+	 && rt->rtmsg_dst.s6_addr32[2] == 0L
+	 && rt->rtmsg_dst.s6_addr32[3] == 0L
+	 && (metric < 0 || rt->rtmsg_metric == metric)) {
+	    result = 1;
+	    break;
+	}
+    }
+
+    close_route_table();
+    return result;
+}
+
+/********************************************************************
+ *
+ * sif6defaultroute - assign a default route through the address given.
+ *
+ * If the global default_rt_repl_rest flag is set, then this function
+ * already replaced the original system defaultroute with some other
+ * route and it should just replace the current defaultroute with
+ * another one, without saving the current route. Use: demand mode,
+ * when pppd sets first a defaultroute it it's temporary ppp0 addresses
+ * and then changes the temporary addresses to the addresses for the real
+ * ppp connection when it has come up.
+ */
+
+int sif6defaultroute (int unit, eui64_t ouraddr, eui64_t gateway)
+{
+    struct in6_rtmsg rt;
+    char buf[IF_NAMESIZE];
+
+    if (defaultroute6_exists(&rt, dfl_route_metric) &&
+	    rt.rtmsg_ifindex != if_nametoindex(ifname)) {
+	if (rt.rtmsg_flags & RTF_GATEWAY)
+	    error("not replacing existing default route via gateway");
+	else
+	    error("not replacing existing default route through %s",
+		  if_indextoname(rt.rtmsg_ifindex, buf));
+	return 0;
+    }
+
+    memset (&rt, 0, sizeof (rt));
+
+    rt.rtmsg_ifindex = if_nametoindex(ifname);
+    rt.rtmsg_metric = dfl_route_metric + 1; /* +1 for binary compatibility */
+    rt.rtmsg_dst_len = 0;
+
+    rt.rtmsg_flags = RTF_UP;
+    if (ioctl(sock6_fd, SIOCADDRT, &rt) < 0) {
+	if ( ! ok_error ( errno ))
+	    error("default route ioctl(SIOCADDRT): %m");
+	return 0;
+    }
+
+    have_default_route6 = 1;
+    return 1;
+}
+
+/********************************************************************
+ *
+ * cif6defaultroute - delete a default route through the address given.
+ */
+
+int cif6defaultroute (int unit, eui64_t ouraddr, eui64_t gateway)
+{
+    struct in6_rtmsg rt;
+
+    have_default_route6 = 0;
+
+    memset (&rt, '\0', sizeof (rt));
+
+    rt.rtmsg_ifindex = if_nametoindex(ifname);
+    rt.rtmsg_metric = dfl_route_metric + 1; /* +1 for binary compatibility */
+    rt.rtmsg_dst_len = 0;
+
+    rt.rtmsg_flags = RTF_UP;
+    if (ioctl(sock6_fd, SIOCDELRT, &rt) < 0 && errno != ESRCH) {
+	if (still_ppp()) {
+	    if ( ! ok_error ( errno ))
+		error("default route ioctl(SIOCDELRT): %m");
+	    return 0;
+	}
+    }
+
+    return 1;
+}
+#endif /* INET6 */
+
 /********************************************************************
  *
  * sifproxyarp - Make a proxy ARP entry for the peer.