PPP, from PPPD upstream, separate IPv6 handling for sifup/sifdown

The current code is buggy regarding handling of link state when using
both IPCP and IPv6CP: if IPv6CP has been set up and if during IPCP
negociation, ipcp_up() fails, it will incorrectly take the interface
down. The simple solution here is to change the platform code to do the
same as on Solaris: separate IPv6CP up/down state handling with sif6up()
and sif6down(), so that we really know when the interface is allowed to
go down.

(Based from pppd commit b04d2dc6df5c6b5650fea44250d58757ee3dac4a)

src/include/netif/ppp/ppp.h

@@ -379,6 +379,11 @@ struct ppp_pcb_s {
 
   /* flags */
   unsigned int if_up                   :1; /* True when the interface is up. */
+#if PPP_IPV6_SUPPORT
+  unsigned int if6_up                  :1; /* True when the IPv6 interface is up. */
+#else
+  unsigned int                         :1; /* 1 bit of padding */
+#endif /* PPP_IPV6_SUPPORT */
   unsigned int pcomp                   :1; /* Does peer accept protocol compression? */
   unsigned int accomp                  :1; /* Does peer accept addr/ctl compression? */
   unsigned int proxy_arp_set           :1; /* Have created proxy arp entry */
@@ -396,7 +401,7 @@ struct ppp_pcb_s {
 #else
   unsigned int                         :1; /* 1 bit of padding */
 #endif /* PPPOS_SUPPORT && VJ_SUPPORT */
-  unsigned int                         :6; /* 5 bits of padding to round out to 16 bits */
+  unsigned int                         :5; /* 5 bits of padding to round out to 16 bits */
 
 #if PPPOS_SUPPORT
 /* FIXME: there is probably one superfluous */

src/include/netif/ppp/ppp_impl.h

@@ -406,6 +406,11 @@ int cdns(ppp_pcb *pcb, u32_t ns1, u32_t ns2);
 int sifup(ppp_pcb *pcb);
 int sifdown (ppp_pcb *pcb);
 
+#if PPP_IPV6_SUPPORT
+int sif6up(ppp_pcb *pcb);
+int sif6down (ppp_pcb *pcb);
+#endif /* PPP_IPV6_SUPPORT */
+
 int sifnpmode(ppp_pcb *pcb, int proto, enum NPmode mode);
 
 void netif_set_mtu(ppp_pcb *pcb, int mtu);

src/netif/ppp/PPPD_FOLLOWUP

@@ -312,3 +312,15 @@ Solaris port, don't care.
   4043750fca36e7e0eb90d702e048ad1da4929418
 
 Just release stuff.
+
+
+2014-02-18 - pppd: Add option "stop-bits" to set number of serial port stop bits.
+  ad993a20ee485f0d0e2ac4105221641b200da6e2
+
+Low level serial port, not in the port.
+
+
+2014-03-09 - pppd: Separate IPv6 handling for sifup/sifdown
+  b04d2dc6df5c6b5650fea44250d58757ee3dac4a
+
+Reimplemented.

src/netif/ppp/ipv6cp.c

@@ -1103,21 +1103,12 @@ static void ipv6_check_options() {
 static int ipv6_demand_conf(int u) {
     ipv6cp_options *wo = &ipv6cp_wantoptions[u];
 
-#if defined(__linux__) || defined(SOL2) || (defined(SVR4) && (defined(SNI) || defined(__USLC__)))
-#if defined(SOL2)
     if (!sif6up(u))
 	return 0;
-#else
-    if (!sifup(u))
-	return 0;
-#endif /* defined(SOL2) */
-#endif    
+
     if (!sif6addr(u, wo->ourid, wo->hisid))
 	return 0;
-#if !defined(__linux__) && !(defined(SVR4) && (defined(SNI) || defined(__USLC__)))
-    if (!sifup(u))
-	return 0;
-#endif
+
     if (!sifnpmode(u, PPP_IPV6, NPMODE_QUEUE))
 	return 0;
 
@@ -1222,8 +1213,8 @@ static void ipv6cp_up(fsm *f) {
 	}
 
 	/* bring the interface up for IPv6 */
-	if (!sifup(f->pcb)) {
-	    PPPDEBUG(LOG_DEBUG, ("sifup failed (IPV6)"));
+	if (!sif6up(f->pcb)) {
+	    PPPDEBUG(LOG_DEBUG, ("sif6up failed (IPV6)"));
 	    ipv6cp_close(f->pcb, "Interface configuration failed");
 	    return;
 	}
@@ -1286,7 +1277,7 @@ static void ipv6cp_down(fsm *f) {
 	ipv6cp_clear_addrs(f->pcb,
 			   go->ourid,
 			   ho->hisid);
-	sifdown(f->pcb);
+	sif6down(f->pcb);
     }
 
 #if 0 /* UNUSED */

src/netif/ppp/ppp.c

@@ -2196,10 +2196,6 @@ int sifup(ppp_pcb *pcb) {
 
   netif_set_addr(&pcb->netif, &pcb->addrs.our_ipaddr, &pcb->addrs.netmask,
                  &pcb->addrs.his_ipaddr);
-#if PPP_IPV6_SUPPORT
-  ip6_addr_copy(pcb->netif.ip6_addr[0], pcb->addrs.our6_ipaddr);
-  netif_ip6_addr_set_state(&pcb->netif, 0, IP6_ADDR_PREFERRED);
-#endif /* PPP_IPV6_SUPPORT */
 
   netif_set_up(&pcb->netif);
   pcb->if_up = 1;
@@ -2221,12 +2217,59 @@ int sifdown(ppp_pcb *pcb) {
     return 1;
 
   pcb->if_up = 0;
-  /* make sure the netif status callback is called */
-  netif_set_down(&pcb->netif);
+
+  if (1
+#if PPP_IPV6_SUPPORT
+   /* set the interface down if IPv6 is down as well */
+   && !pcb->if6_up
+#endif /* PPP_IPV6_SUPPORT */
+  ) {
+    /* make sure the netif status callback is called */
+    netif_set_down(&pcb->netif);
+  }
   PPPDEBUG(LOG_DEBUG, ("sifdown: unit %d: err_code=%d\n", pcb->num, pcb->err_code));
   return 1;
 }
 
+#if PPP_IPV6_SUPPORT
+/*
+ * sif6up - Config the interface up and enable IPv6 packets to pass.
+ */
+int sif6up(ppp_pcb *pcb) {
+
+  ip6_addr_copy(pcb->netif.ip6_addr[0], pcb->addrs.our6_ipaddr);
+  netif_ip6_addr_set_state(&pcb->netif, 0, IP6_ADDR_PREFERRED);
+
+  netif_set_up(&pcb->netif);
+  pcb->if6_up = 1;
+  pcb->err_code = PPPERR_NONE;
+
+  PPPDEBUG(LOG_DEBUG, ("sif6up: unit %d: err_code=%d\n", pcb->num, pcb->err_code));
+  pcb->link_status_cb(pcb, pcb->err_code, pcb->ctx_cb);
+  return 1;
+}
+
+/********************************************************************
+ *
+ * sif6down - Disable the indicated protocol and config the interface
+ *	      down if there are no remaining protocols.
+ */
+int sif6down(ppp_pcb *pcb) {
+
+  if(!pcb->if6_up)
+    return 1;
+
+  pcb->if6_up = 0;
+  /* set the interface down if IPv4 is down as well */
+  if (!pcb->if_up) {
+    /* make sure the netif status callback is called */
+    netif_set_down(&pcb->netif);
+  }
+  PPPDEBUG(LOG_DEBUG, ("sif6down: unit %d: err_code=%d\n", pcb->num, pcb->err_code));
+  return 1;
+}
+#endif /* PPP_IPV6_SUPPORT */
+
 /*
  * sifnpmode - Set the mode for handling packets for a given NP.
  */