From: Nicolas BESNARD <nico.besnard31@gmail.com>
Date: Mon, 30 Sep 2024 09:58:35 +0000 (+0200)
Subject: dscp: add option to set dscp value
X-Git-Url: http://git.openwrt.org/?a=commitdiff_plain;h=1b5f0c402bbf8ccae87816a3ced9d509c643778a;p=project%2Fodhcp6c.git

dscp: add option to set dscp value

Problem: odhcp6c doesn't support change of DSCP value.

Solution: Adapt odhcp6c to set socket option to change the DSCP value
for dhcpv6 packets.

Signed-off-by: Nicolas BESNARD <nico.besnard31@gmail.com>
Signed-off-by: Paul Donald <newtwen+github@gmail.com>
Link: https://github.com/openwrt/odhcp6c/pull/106
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 50b6f7b..3985927 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -193,7 +193,7 @@ static char *dhcpv6_status_code_to_str(uint16_t code)
 	return "Unknown";
 }
 
-int init_dhcpv6(const char *ifname, unsigned int options, int sk_prio, int sol_timeout)
+int init_dhcpv6(const char *ifname, unsigned int options, int sk_prio, int sol_timeout, unsigned int dscp)
 {
 	client_options = options;
 	dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
@@ -287,6 +287,11 @@ int init_dhcpv6(const char *ifname, unsigned int options, int sk_prio, int sol_t
 	if (setsockopt(sock, SOL_SOCKET, SO_PRIORITY, &sk_prio, sizeof(sk_prio)) < 0)
 		goto failure;
 
+	val = dscp << 2;
+	if (setsockopt(sock, IPPROTO_IPV6, IPV6_TCLASS, &val, sizeof(val)) < 0) {
+		goto failure;
+	}
+
 	struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 		.sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 
diff --git a/src/odhcp6c.c b/src/odhcp6c.c
index 8354820..f439901 100644
--- a/src/odhcp6c.c
+++ b/src/odhcp6c.c
@@ -187,8 +187,9 @@ int main(_unused int argc, char* const argv[])
 	unsigned int client_options = DHCPV6_CLIENT_FQDN | DHCPV6_ACCEPT_RECONFIGURE;
 	unsigned int ra_options = RA_RDNSS_DEFAULT_LIFETIME;
 	unsigned int ra_holdoff_interval = RA_MIN_ADV_INTERVAL;
+	unsigned int dscp = 0;
 
-	while ((c = getopt(argc, argv, "S::DN:V:P:FB:c:i:r:Ru:Ux:s:kK:t:m:Lhedp:fav")) != -1) {
+	while ((c = getopt(argc, argv, "S::DN:V:P:FB:c:i:r:Ru:Ux:s:kK:t:C:m:Lhedp:fav")) != -1) {
 		switch (c) {
 		case 'S':
 			allow_slaac_only = (optarg) ? atoi(optarg) : -1;
@@ -366,6 +367,14 @@ int main(_unused int argc, char* const argv[])
 			sol_timeout = atoi(optarg);
 			break;
 
+		case 'C':
+			dscp = atoi(optarg);
+			if (dscp > 63) {
+				dscp = 0;
+				syslog(LOG_ERR, "Invalid DSCP value, using default (0)");
+			}
+			break;
+
 		case 'm':
 			ra_holdoff_interval = atoi(optarg);
 			break;
@@ -453,13 +462,13 @@ int main(_unused int argc, char* const argv[])
 		}
 	}
 
-    if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
-            init_dhcpv6(ifname, client_options, sk_prio, sol_timeout) ||
-            ra_init(ifname, &ifid, ra_options, ra_holdoff_interval) ||
-            script_init(script, ifname)) {
-        syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
-        return 4;
-     }
+	if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
+			init_dhcpv6(ifname, client_options, sk_prio, sol_timeout, dscp) ||
+			ra_init(ifname, &ifid, ra_options, ra_holdoff_interval) ||
+			script_init(script, ifname)) {
+		syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
+		return 4;
+	}
 
     script_call("started", 0, false);
 
@@ -648,6 +657,7 @@ static int usage(void)
 	"	-f		Don't send Client FQDN option\n"
 	"	-k		Don't send a RELEASE when stopping\n"
 	"	-K <sk-prio>	Set packet kernel priority (0)\n"
+	"	-C <dscp>	Set packet DSCP value (0)\n"
 	"	-t <seconds>	Maximum timeout for DHCPv6-SOLICIT (120)\n"
 	"	-m <seconds>	Minimum time between accepting RA updates (3)\n"
 	"	-L		Ignore default lifetime for RDNSS records\n"
diff --git a/src/odhcp6c.h b/src/odhcp6c.h
index 518193e..8bba932 100644
--- a/src/odhcp6c.h
+++ b/src/odhcp6c.h
@@ -393,7 +393,7 @@ struct odhcp6c_opt {
 	const char *str;
 };
 
-int init_dhcpv6(const char *ifname, unsigned int client_options, int sk_prio, int sol_timeout);
+int init_dhcpv6(const char *ifname, unsigned int client_options, int sk_prio, int sol_timeout, unsigned int dscp);
 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd, bool stateful_only);
 int dhcpv6_request(enum dhcpv6_msg type);
 int dhcpv6_poll_reconfigure(void);