From: Steven Barth <steven@midlink.org>
Date: Fri, 10 Apr 2015 11:19:44 +0000 (+0200)
Subject: Pass ICMP configuration to user-space instead of directly applying it
X-Git-Tag: debian/1.1+git20160131-1~25
X-Git-Url: https://git.decadent.org.uk/gitweb/?p=odhcp6c.git;a=commitdiff_plain;h=2bf5f3ad1ce6d386938c39d1569f2635300eca6e

Pass ICMP configuration to user-space instead of directly applying it
---

diff --git a/README b/README
index 8c66ffa..9b56b20 100644
--- a/README
+++ b/README
@@ -29,8 +29,7 @@ especially routers. It compiles to only about 35 KB (-Os -s).
 	h) Configurable SOL_MAX_RT
 	i) DS-Lite AFTR-Name Option
 	j) Softwire address and port mapped clients (MAP, LW4over6)
-	k) Prefix Class (experimental)
-	l) CER-ID (experimental)
+	j) CER-ID (experimental)
 
 4. Support for requesting and parsing Router Advertisements
 	a) parsing of prefixes, routes, MTU and RDNSS options
@@ -78,5 +77,9 @@ Environment:
 * RA_ROUTES		A space-separated list of routes from the RA
 				Format: <address>/<length>,gateway,valid,metric
 * RA_DNS		A space-separated list of recursive DNS servers from the RA
+* RA_HOPLIMIT	Highest hop-limit received in RAs
+* RA_MTU		MTU-value received in RA
+* RA_REACHABLE	ND Reachability time
+* RA_RETRANSMIT	ND Retransmit time
 * AFTR			The DS-Lite AFTR domain name
 * MAPE / MAPT / LW4O6	Softwire rules for MAPE, MAPT and LW4O6
diff --git a/src/odhcp6c.h b/src/odhcp6c.h
index 3e2713e..ff5b9e4 100644
--- a/src/odhcp6c.h
+++ b/src/odhcp6c.h
@@ -319,6 +319,11 @@ int init_rtnetlink(void);
 int set_rtnetlink_addr(int ifindex, const struct in6_addr *addr,
 		uint32_t pref, uint32_t valid);
 
+int ra_conf_hoplimit(int newvalue);
+int ra_conf_mtu(int newvalue);
+int ra_conf_reachable(int newvalue);
+int ra_conf_retransmit(int newvalue);
+
 int script_init(const char *path, const char *ifname);
 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src);
 void script_call(const char *status);
diff --git a/src/ra.c b/src/ra.c
index 09d5c1d..04764c7 100644
--- a/src/ra.c
+++ b/src/ra.c
@@ -165,19 +165,6 @@ static int16_t pref_to_priority(uint8_t flags)
 }
 
 
-static int update_proc(const char *sect, const char *opt, uint32_t value)
-{
-	char buf[64];
-	snprintf(buf, sizeof(buf), "/proc/sys/net/ipv6/%s/%s/%s", sect, if_name, opt);
-
-	int fd = open(buf, O_WRONLY);
-	int ret = write(fd, buf, snprintf(buf, sizeof(buf), "%u", value));
-	close(fd);
-
-	return ret;
-}
-
-
 bool ra_link_up(void)
 {
 	static bool firstcall = true;
@@ -249,6 +236,38 @@ static bool ra_icmpv6_valid(struct sockaddr_in6 *source, int hlim, uint8_t *data
 	return opt == end;
 }
 
+int ra_conf_hoplimit(int newvalue)
+{
+	static int value = 0;
+	if (newvalue > value)
+		value = newvalue;
+	return value;
+}
+
+int ra_conf_mtu(int newvalue)
+{
+	static int value = 0;
+	if (newvalue >= 1280 && newvalue <= 65535)
+		value = newvalue;
+	return value;
+}
+
+int ra_conf_reachable(int newvalue)
+{
+	static int value = 0;
+	if (newvalue > 0 && newvalue <= 3600000)
+		value = newvalue;
+	return value;
+}
+
+int ra_conf_retransmit(int newvalue)
+{
+	static int value = 0;
+	if (newvalue > 0 && newvalue <= 60000)
+		value = newvalue;
+	return value;
+}
+
 bool ra_process(void)
 {
 	bool found = false;
@@ -324,26 +343,18 @@ bool ra_process(void)
 		changed |= odhcp6c_update_entry(STATE_RA_ROUTE, &entry, 0, true);
 
 		// Parse hoplimit
-		if (adv->nd_ra_curhoplimit)
-			update_proc("conf", "hop_limit", adv->nd_ra_curhoplimit);
+		ra_conf_hoplimit(adv->nd_ra_curhoplimit);
 
 		// Parse ND parameters
-		uint32_t reachable = ntohl(adv->nd_ra_reachable);
-		if (reachable > 0 && reachable <= 3600000)
-			update_proc("neigh", "base_reachable_time_ms", reachable);
-
-		uint32_t retransmit = ntohl(adv->nd_ra_retransmit);
-		if (retransmit > 0 && retransmit <= 60000)
-			update_proc("neigh", "retrans_time_ms", retransmit);
-
+		ra_conf_reachable(ntohl(adv->nd_ra_reachable));
+		ra_conf_retransmit(ntohl(adv->nd_ra_retransmit));
 
 		// Evaluate options
 		struct icmpv6_opt *opt;
 		icmpv6_for_each_option(opt, &adv[1], &buf[len]) {
 			if (opt->type == ND_OPT_MTU) {
 				uint32_t *mtu = (uint32_t*)&opt->data[2];
-				if (ntohl(*mtu) >= 1280 && ntohl(*mtu) <= 65535)
-					update_proc("conf", "mtu", ntohl(*mtu));
+				ra_conf_mtu(ntohl(*mtu));
 			} else if (opt->type == ND_OPT_ROUTE_INFORMATION && opt->len <= 3) {
 				entry.router = from.sin6_addr;
 				entry.target = any;
diff --git a/src/script.c b/src/script.c
index d993277..2c34216 100644
--- a/src/script.c
+++ b/src/script.c
@@ -184,6 +184,15 @@ static void entry_to_env(const char *name, const void *data, size_t len, enum en
 }
 
 
+static void int_to_env(const char *name, int value)
+{
+	size_t len = 12 + strlen(name);
+	char *buf = realloc(NULL, len);
+	snprintf(buf, len, "%s=%d", name, value);
+	putenv(buf);
+}
+
+
 static void s46_to_env_portparams(const uint8_t *data, size_t len, FILE *fp)
 {
 	uint8_t *odata;
@@ -366,6 +375,11 @@ void script_call(const char *status)
 		entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 		entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 
+		int_to_env("RA_HOPLIMIT", ra_conf_hoplimit(0));
+		int_to_env("RA_MTU", ra_conf_mtu(0));
+		int_to_env("RA_REACHABLE", ra_conf_reachable(0));
+		int_to_env("RA_RETRANSMIT", ra_conf_retransmit(0));
+
 		char *buf = malloc(10 + passthru_len * 2);
 		strncpy(buf, "PASSTHRU=", 10);
 		script_hexlify(&buf[9], passthru, passthru_len);