Merge pull request #189 from initramfs/auto-ignore-prefixes

Add autoignoreprefixes option to interface options

gram.y

@@ -57,6 +57,7 @@ int yylex_destroy (void);
 %token		T_ABRO
 %token		T_RASRCADDRESS
 %token		T_NAT64PREFIX
+%token		T_AUTOIGNOREPREFIX
 
 %token	<str>	STRING
 %token	<num>	NUMBER
@@ -143,6 +144,7 @@ int yylex_destroy (void);
 %type   <num>	number_or_infinity
 %type	<rasrcaddressinfo> rasrcaddresslist v6addrlist_rasrcaddress
 %type	<nat64pinfo> nat64prefixdef
+%type	<igpinfo> ignoreprefixlist ignoreprefixes
 
 %union {
 	unsigned int		num;
@@ -159,6 +161,7 @@ int yylex_destroy (void);
 	struct AdvAbro		*abroinfo;
 	struct AdvRASrcAddress	*rasrcaddressinfo;
 	struct NAT64Prefix	*nat64pinfo;
+	struct AutogenIgnorePrefix	*igpinfo;
 };
 
 %{
@@ -245,6 +248,7 @@ ifaceparam 	: ifaceval
 		| abrodef       { ADD_TO_LL(struct AdvAbro, AdvAbroList, $1); }
 		| rasrcaddresslist { ADD_TO_LL(struct AdvRASrcAddress, AdvRASrcAddressList, $1); }
 		| nat64prefixdef { ADD_TO_LL(struct NAT64Prefix, NAT64PrefixList, $1); }
+		| ignoreprefixlist { ADD_TO_LL(struct AutogenIgnorePrefix, IgnorePrefixList, $1); }
 		;
 
 ifaceval	: T_MinRtrAdvInterval NUMBER ';'
@@ -572,6 +576,59 @@ nat64prefixparms : T_AdvValidLifetime NUMBER ';'
 		}
 		;
 
+ignoreprefixlist	: T_AUTOIGNOREPREFIX '{' ignoreprefixes '}' ';'
+		{
+			$$ = $3;
+		}
+		;
+
+ignoreprefixes	: IPV6ADDR '/' NUMBER ';'
+		{
+			struct AutogenIgnorePrefix *new = calloc(1, sizeof(struct AutogenIgnorePrefix));
+			if (new == NULL) {
+				flog(LOG_CRIT, "calloc failed: %s", strerror(errno));
+				ABORT;
+			}
+
+			memcpy(&(new->Prefix), $1, sizeof(struct in6_addr));
+
+			// Create subnet mask from CIDR notation
+			int fullOctets = $3 / 8;
+			for (int i = 0; i < fullOctets; ++i) {
+				new->Mask.s6_addr[i] = 0xff;
+			}
+
+			if (fullOctets != 16) {
+				new->Mask.s6_addr[fullOctets] = ~(1 << (8 - $3 % 8)) + 1;
+			}
+
+			$$ = new;
+		}
+		| ignoreprefixes IPV6ADDR '/' NUMBER ';'
+		{
+			struct AutogenIgnorePrefix *new = calloc(1, sizeof(struct AutogenIgnorePrefix));
+			if (new == NULL) {
+				flog(LOG_CRIT, "calloc failed: %s", strerror(errno));
+				ABORT;
+			}
+
+			memcpy(&(new->Prefix), $2, sizeof(struct in6_addr));
+
+			// Create subnet mask from CIDR notation
+			int fullOctets = $4 / 8;
+			for (int i = 0; i < fullOctets; ++i) {
+				new->Mask.s6_addr[i] = 0xff;
+			}
+
+			if (fullOctets != 16) {
+				new->Mask.s6_addr[fullOctets] = ~(1 << (8 - $4 % 8)) + 1;
+			}
+
+			new->next = $1;
+			$$ = new;
+		}
+		;
+
 prefixdef	: prefixhead optional_prefixplist ';'
 		{
 			if (prefix) {

interface.c

@@ -436,6 +436,14 @@ static void free_iface_list(struct Interface *iface)
 			dnssl = next_dnssl;
 		}
 
+		struct AutogenIgnorePrefix *ignore_prefixes = iface->IgnorePrefixList;
+		while (ignore_prefixes) {
+			struct AutogenIgnorePrefix *next_ignore_prefix = ignore_prefixes->next;
+
+			free(ignore_prefixes);
+			ignore_prefixes = next_ignore_prefix;
+		}
+
 		struct Clients *clients = iface->ClientList;
 		while (clients) {
 			struct Clients *next_client = clients->next;

radvd.conf.5.man

@@ -33,6 +33,7 @@ The file contains one or more interface definitions of the form:
 	list of DNSSL definitions
 	list of ABRO definitions
 	list of NAT64 pref64 definitions
+	list of auto-ignore prefixes
 	list of acceptable RA source addresses
 .B };
 .fi
@@ -56,8 +57,9 @@ Special prefix "::/64" is also supported on systems that implement getifaddrs()
 (on other systems, configuration activation fails and radvd exits).
 When configured, radvd
 picks all non-link-local prefix assigned to the interface and starts advertising
-it.  This may be applicable in non-6to4 scenarios where the upstream prefix might
-change.  This option is incompatible with Base6to4Interface option.
+it (unless ignored with autoignoreprefixes).  This may be applicable in non-6to4
+scenarios where the upstream prefix might change.  This option is incompatible
+with Base6to4Interface option.
 AdvRouterAddr option is always enabled when this configuration is used.
 
 All the possible prefix specific options are described below.  Each
@@ -144,6 +146,18 @@ The value of
 .B length
 can only be one of /32, /40, /48, /56, /64, or /96.
 
+When using the special prefix "::/64" this option forms an ignore list for
+prefixes that should not be automatically generated and advertised. Has no
+effect on any other prefix definition.
+
+The definitions are of the form:
+
+.nf
+.BR autoignoreprefixes " " {
+        list of IPv6 prefixes
+.B };
+.fi
+
 .SH INTERFACE SPECIFIC OPTIONS
 
 .TP

radvd.h

@@ -30,6 +30,7 @@ extern int disableigmp6check;
 
 struct AdvPrefix;
 struct NAT64Prefix;
+struct AutogenIgnorePrefix;
 struct Clients;
 
 #define HWADDR_MAX 16
@@ -107,6 +108,8 @@ struct Interface {
 
 	struct NAT64Prefix *NAT64PrefixList;
 
+	struct AutogenIgnorePrefix *IgnorePrefixList;
+
 	uint32_t AdvLinkMTU; /* XXX: sllao also has an if_maxmtu value...Why? */
 	uint32_t AdvRAMTU;   /* MTU used for RA */
 
@@ -179,6 +182,13 @@ struct NAT64Prefix {
 	struct NAT64Prefix *next;
 };
 
+struct AutogenIgnorePrefix {
+	struct in6_addr Prefix;
+	struct in6_addr Mask;
+
+	struct AutogenIgnorePrefix *next;
+};
+
 /* More-Specific Routes extensions */
 
 struct AdvRoute {

scanner.l

@@ -52,6 +52,7 @@ clients			{ return T_CLIENTS; }
 lowpanco		{ return T_LOWPANCO; }
 abro			{ return T_ABRO; }
 nat64prefix		{ return T_NAT64PREFIX; }
+autoignoreprefixes	{ return T_AUTOIGNOREPREFIX; }
 
 AdvRASrcAddress	{ return T_RASRCADDRESS; }
 

send.c

@@ -410,8 +410,24 @@ static struct safe_buffer_list *add_auto_prefixes(struct safe_buffer_list *sbl,
 		if (IN6_IS_ADDR_LINKLOCAL(&s6->sin6_addr))
 			continue;
 
+		struct in6_addr prefix6 = get_prefix6(&s6->sin6_addr, &mask->sin6_addr);
+
+		int ignore = 0;
+		for (struct AutogenIgnorePrefix *current = iface->IgnorePrefixList; current; current = current->next) {
+			struct in6_addr candidatePrefix6 = get_prefix6(&current->Prefix, &current->Mask);
+
+			if (memcmp(&prefix6, &candidatePrefix6, sizeof(struct in6_addr)) == 0 &&
+			    memcmp(&mask->sin6_addr, &current->Mask, sizeof(struct in6_addr)) == 0) {
+				ignore = 1;
+				break;
+			}
+		}
+
+		if (ignore)
+			continue;
+
 		xprefix = *prefix;
-		xprefix.Prefix = get_prefix6(&s6->sin6_addr, &mask->sin6_addr);
+		xprefix.Prefix = prefix6;
 		xprefix.PrefixLen = count_mask(mask);
 
 		char pfx_str[INET6_ADDRSTRLEN];