From: Roy Marples <roy@marples.name>
Date: Mon, 15 Jun 2020 14:51:17 +0000 (+0100)
Subject: DHCP6: Use sla setting when calculating delegated prefix length
X-Git-Tag: v9.1.2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d1913fa8a17cc495104eaecf3e71c62e21a18cc8;p=thirdparty%2Fdhcpcd.git

DHCP6: Use sla setting when calculating delegated prefix length

This is fine as we have a limited list of interfaces we're
delegating to so we know all the numbers.
This fixes an issue where an interface index could exceed 8 bits.

While here change sla_set to a boolean.
---

diff --git a/src/dhcp6.c b/src/dhcp6.c
index 70d56a81..da472b9d 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -541,12 +541,12 @@ dhcp6_delegateaddr(struct in6_addr *addr, struct interface *ifp,
 		state->reason = "DELEGATED6";
 	}
 
-	if (sla == NULL || sla->sla_set == 0) {
+	if (sla == NULL || !sla->sla_set) {
 		/* No SLA set, so make an assumption of
 		 * desired SLA and prefix length. */
 		asla.sla = ifp->index;
 		asla.prefix_len = 0;
-		asla.sla_set = 0;
+		asla.sla_set = false;
 		sla = &asla;
 	} else if (sla->prefix_len == 0) {
 		/* An SLA was given, but prefix length was not.
@@ -554,7 +554,7 @@ dhcp6_delegateaddr(struct in6_addr *addr, struct interface *ifp,
 		 * potentially more than one interface. */
 		asla.sla = sla->sla;
 		asla.prefix_len = 0;
-		asla.sla_set = 0;
+		asla.sla_set = sla->sla_set;
 		sla = &asla;
 	}
 
@@ -562,16 +562,15 @@ dhcp6_delegateaddr(struct in6_addr *addr, struct interface *ifp,
 		uint32_t sla_max;
 		int bits;
 
-		if (ia->sla_max == 0) {
+		sla_max = ia->sla_max;
+		if (sla_max == 0 && (sla == NULL || !sla->sla_set)) {
 			const struct interface *ifi;
 
-			sla_max = 0;
 			TAILQ_FOREACH(ifi, ifp->ctx->ifaces, next) {
 				if (ifi->index > sla_max)
 					sla_max = ifi->index;
 			}
-		} else
-			sla_max = ia->sla_max;
+		}
 
 		bits = fls32(sla_max);
 
diff --git a/src/if-options.c b/src/if-options.c
index 3dde04bf..1b66f758 100644
--- a/src/if-options.c
+++ b/src/if-options.c
@@ -1460,7 +1460,7 @@ parse_option(struct dhcpcd_ctx *ctx, const char *ifname, struct if_options *ifo,
 				logerrx("%s: interface name too long", arg);
 				goto err_sla;
 			}
-			sla->sla_set = 0;
+			sla->sla_set = false;
 			sla->prefix_len = 0;
 			sla->suffix = 1;
 			p = np;
@@ -1471,7 +1471,7 @@ parse_option(struct dhcpcd_ctx *ctx, const char *ifname, struct if_options *ifo,
 				if (*p != '\0') {
 					sla->sla = (uint32_t)strtou(p, NULL,
 					    0, 0, UINT32_MAX, &e);
-					sla->sla_set = 1;
+					sla->sla_set = true;
 					if (e) {
 						logerrx("%s: failed to convert "
 						    "sla",
@@ -1530,7 +1530,7 @@ parse_option(struct dhcpcd_ctx *ctx, const char *ifname, struct if_options *ifo,
 					    sla->ifname);
 					goto err_sla;
 				}
-				if (sla->sla_set == 0 &&
+				if (!sla->sla_set &&
 				    strcmp(slap->ifname, sla->ifname) == 0)
 				{
 					logwarnx("%s: cannot specify the "
diff --git a/src/if-options.h b/src/if-options.h
index 870eabf6..2c974f57 100644
--- a/src/if-options.h
+++ b/src/if-options.h
@@ -188,7 +188,7 @@ struct if_sla {
 	uint32_t sla;
 	uint8_t prefix_len;
 	uint64_t suffix;
-	int8_t sla_set;
+	bool sla_set;
 };
 
 struct if_ia {