From: Roy Marples <roy@marples.name>
Date: Wed, 5 Jun 2013 10:37:45 +0000 (+0000)
Subject: Support the DHCPv6 unicast option.
X-Git-Tag: v6.0.0~54
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=be2a8dac4e88d607390966ae0cf77a98fcb83310;p=thirdparty%2Fdhcpcd.git

Support the DHCPv6 unicast option.
---

diff --git a/dhcp6.c b/dhcp6.c
index d3706b95..026cc6c3 100644
--- a/dhcp6.c
+++ b/dhcp6.c
@@ -69,7 +69,9 @@
 //#define VENDOR_SPLIT
 
 static int sock = -1;
-static struct sockaddr_in6 alldhcp, from;
+static struct in6_addr in6addr_linklocal_alldhcp =
+    IN6ADDR_LINKLOCAL_ALLDHCP_INIT;
+static struct sockaddr_in6 from;
 static struct msghdr sndhdr;
 static struct iovec sndiov[2];
 static unsigned char *sndbuf;
@@ -158,15 +160,6 @@ dhcp6_init(void)
 	atexit(dhcp6_cleanup);
 #endif
 
-	memset(&alldhcp, 0, sizeof(alldhcp));
-	alldhcp.sin6_family = AF_INET6;
-	alldhcp.sin6_port = htons(DHCP6_SERVER_PORT);
-#ifdef SIN6_LEN
-	alldhcp.sin6_len = sizeof(alldhcp);
-#endif
-	if (inet_pton(AF_INET6, ALLDHCP, &alldhcp.sin6_addr.s6_addr) != 1)
-		return -1;
-
 	len = CMSG_SPACE(sizeof(struct in6_pktinfo));
 	sndbuf = calloc(1, len);
 	if (sndbuf == NULL)
@@ -358,7 +351,7 @@ dhcp6_makemessage(struct interface *ifp)
 	struct dhcp6_state *state;
 	struct dhcp6_message *m;
 	struct dhcp6_option *o, *so;
-	const struct dhcp6_option *si;
+	const struct dhcp6_option *si, *unicast;
 	ssize_t len, ml;
 	size_t l;
 	uint8_t u8;
@@ -386,7 +379,7 @@ dhcp6_makemessage(struct interface *ifp)
 				len += sizeof(*u16);
 		}
 		if (len == 0)
-			len = sizeof(*u16) * 2;
+			len = sizeof(*u16) * 3;
 		len += sizeof(*o);
 	}
 
@@ -451,6 +444,8 @@ dhcp6_makemessage(struct interface *ifp)
 		return -1;
 
 	state->send_len = len;
+	unicast = NULL;
+	/* Depending on state, get the unicast address */
 	switch(state->state) {
 		break;
 	case DH6S_INIT: /* FALLTHROUGH */
@@ -459,6 +454,7 @@ dhcp6_makemessage(struct interface *ifp)
 		break;
 	case DH6S_REQUEST:
 		state->send->type = DHCP6_REQUEST;
+		unicast = dhcp6_getoption(D6_OPTION_UNICAST, m, ml);
 		break;
 	case DH6S_CONFIRM:
 		state->send->type = DHCP6_CONFIRM;
@@ -468,12 +464,14 @@ dhcp6_makemessage(struct interface *ifp)
 		break;
 	case DH6S_RENEW:
 		state->send->type = DHCP6_RENEW;
+		unicast = dhcp6_getoption(D6_OPTION_UNICAST, m, ml);
 		break;
 	case DH6S_INFORM:
 		state->send->type = DHCP6_INFORMATION_REQ;
 		break;
 	case DH6S_RELEASE:
 		state->send->type = DHCP6_RELEASE;
+		unicast = dhcp6_getoption(D6_OPTION_UNICAST, m, ml);
 		break;
 	default:
 		errno = EINVAL;
@@ -482,6 +480,13 @@ dhcp6_makemessage(struct interface *ifp)
 		return -1;
 	}
 
+	/* If we found a unicast option, copy it to our state for sending */
+	if (unicast && ntohs(unicast->len) == sizeof(state->unicast.s6_addr))
+		memcpy(&state->unicast.s6_addr, D6_COPTION_DATA(unicast),
+		    sizeof(state->unicast.s6_addr));
+	else
+		state->unicast = in6addr_any;
+
 	dhcp6_newxid(ifp, state->send);
 
 	o = D6_FIRST_OPTION(state->send);
@@ -578,7 +583,8 @@ dhcp6_makemessage(struct interface *ifp)
 		if (o->len == 0) {
 			*u16++ = htons(D6_OPTION_DNS_SERVERS);
 			*u16++ = htons(D6_OPTION_DOMAIN_LIST);
-			o->len = sizeof(*u16) * 2;
+			*u16++ = htons(D6_OPTION_UNICAST);
+			o->len = sizeof(*u16) * 3;
 		}
 		o->len = htons(o->len);
 	}
@@ -638,11 +644,36 @@ dhcp6_sendmessage(struct interface *ifp, void (*callback)(void *))
 	double rnd;
 	suseconds_t ms;
 	uint8_t neg;
+	const char *broad_uni;
+
+	memset(&to, 0, sizeof(to));
+	to.sin6_family = AF_INET6;
+	to.sin6_port = htons(DHCP6_SERVER_PORT);
+#ifdef SIN6_LEN
+	to.sin6_len = sizeof(to);
+#endif
 
 	state = D6_STATE(ifp);
+	/* We need to ensure we have sufficient scope to unicast the address */
+	/* XXX FIXME: We should check any added addresses we have like from
+	 * a Router Advertisement */
+	if (!IN6_IS_ADDR_UNSPECIFIED(&state->unicast) &&
+	    state->state == DH6S_REQUEST &&
+	    (!IN6_IS_ADDR_LINKLOCAL(&state->unicast) || !ipv6_linklocal(ifp)))
+		state->unicast = in6addr_any;
+
+	if (IN6_IS_ADDR_UNSPECIFIED(&state->unicast)) {
+		to.sin6_addr = in6addr_linklocal_alldhcp;
+		broad_uni = "broadcasting";
+	} else {
+		to.sin6_addr = state->unicast;
+		broad_uni = "unicasting";
+	}
+
 	if (!callback)
-		syslog(LOG_DEBUG, "%s: sending %s with xid 0x%02x%02x%02x",
+		syslog(LOG_DEBUG, "%s: %s %s with xid 0x%02x%02x%02x",
 		    ifp->name,
+		    broad_uni,
 		    dhcp6_get_op(state->send->type),
 		    state->send->xid[0],
 		    state->send->xid[1],
@@ -687,9 +718,11 @@ dhcp6_sendmessage(struct interface *ifp, void (*callback)(void *))
 		}
 
 		syslog(LOG_DEBUG,
-		    "%s: sending %s (xid 0x%02x%02x%02x),"
+		    "%s: %s %s (xid 0x%02x%02x%02x),"
 		    " next in %0.2f seconds",
-		    ifp->name, dhcp6_get_op(state->send->type),
+		    ifp->name,
+		    broad_uni,
+		    dhcp6_get_op(state->send->type),
 		    state->send->xid[0],
 		    state->send->xid[1],
 		    state->send->xid[2],
@@ -699,7 +732,6 @@ dhcp6_sendmessage(struct interface *ifp, void (*callback)(void *))
 	/* Update the elapsed time */
 	dhcp6_updateelapsed(ifp, state->send, state->send_len);
 
-	to = alldhcp;
 	to.sin6_scope_id = ifp->index;
 	sndhdr.msg_name = (caddr_t)&to;
 	sndhdr.msg_iov[0].iov_base = (caddr_t)state->send;
diff --git a/dhcp6.h b/dhcp6.h
index 151c3f5e..7189145d 100644
--- a/dhcp6.h
+++ b/dhcp6.h
@@ -30,7 +30,9 @@
 
 #include "dhcpcd.h"
 
-#define ALLDHCP "ff02::1:2"
+#define IN6ADDR_LINKLOCAL_ALLDHCP_INIT \
+	{{{ 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, \
+	    0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02 }}}
 
 /* UDP port numbers for DHCP */
 #define DHCP6_CLIENT_PORT	546
@@ -177,6 +179,7 @@ struct dhcp6_state {
 	uint32_t renew;
 	uint32_t rebind;
 	uint32_t expire;
+	struct in6_addr unicast;
 	struct ipv6_addrhead addrs;
 	uint32_t lowpl;
 	uint32_t sla;