From: Simon Kuenzer <simon@unikraft.io>
Date: Fri, 8 Dec 2023 00:03:06 +0000 (+0100)
Subject: init: Support setting statically assigned DNS server addresses
X-Git-Tag: RELEASE-0.16.2~8
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=3df429f522806ecdf31b15578926bbbb998a3525;p=unikraft%2Flibs%2Flwip.git

init: Support setting statically assigned DNS server addresses

This commit introduces support for setting DNS server addresses to
lwIP's DNS subsystem. The information is found on uknetdev's extended
information fields `UK_NETDEV_IPV4_DNS0` and `UK_NETDEV_IPV4_DNS1`.

Signed-off-by: Simon Kuenzer <simon@unikraft.io>
Reviewed-by: Stefan Jumarea <stefanjumarea02@gmail.com>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
GitHub-Closes: #42
---

diff --git a/init.c b/init.c
index 7d9b13d..5aaf2fd 100644
--- a/init.c
+++ b/init.c
@@ -36,6 +36,7 @@
 #include "lwip/opt.h"
 #include "lwip/tcpip.h"
 #include "lwip/init.h"
+#include "lwip/dns.h"
 #include "lwip/dhcp.h"
 #include "lwip/inet.h"
 #if CONFIG_LWIP_NOTHREADS
@@ -148,6 +149,10 @@ static int liblwip_init(struct uk_init_ctx *ictx __unused)
 	ip4_addr_t gw4;
 	ip4_addr_t *gw4_arg;
 	const char *hostname_arg;
+#if LWIP_DNS
+	ip4_addr_t dns4;
+	unsigned int nb_dns4 = 0;
+#endif /* LWIP_DNS */
 #endif /* LWIP_IPV4 */
 #endif /* CONFIG_LWIP_UKNETDEV && CONFIG_LWIP_AUTOIFACE */
 
@@ -361,6 +366,45 @@ no_conf:
 		uk_pr_info("\n");
 #endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */
 
+#if LWIP_IPV4 && LWIP_DNS
+		/* Primary DNS */
+		if (nb_dns4 < DNS_MAX_SERVERS) {
+			strcfg = uk_netdev_einfo_get(dev, UK_NETDEV_IPV4_DNS0);
+			if (strcfg) {
+				if (ip4addr_aton(strcfg, &dns4) != 1) {
+					uk_pr_err("Failed to parse DNS server address: %s\n",
+						  strcfg);
+					goto dns_secondary;
+				}
+
+				dns_setserver(nb_dns4++, &dns4);
+				uk_pr_info("%c%c%u: Primary DNS server: %s\n",
+					   nf->name[0], nf->name[1], nf->num,
+					   strcfg);
+			}
+		}
+
+dns_secondary:
+		/* Secondary DNS */
+		if (nb_dns4 < DNS_MAX_SERVERS) {
+			strcfg = uk_netdev_einfo_get(dev, UK_NETDEV_IPV4_DNS1);
+			if (strcfg) {
+				if (ip4addr_aton(strcfg, &dns4) != 1) {
+					uk_pr_err("Failed to parse DNS server address: %s\n",
+						  strcfg);
+					goto dns_done;
+				}
+
+				dns_setserver(nb_dns4++, &dns4);
+				uk_pr_info("%c%c%u: Secondary DNS server: %s\n",
+					   nf->name[0], nf->name[1], nf->num,
+					   strcfg);
+			}
+		}
+
+dns_done:
+#endif /* LWIP_IPV4 && LWIP_DNS */
+
 		/* Declare the first network device as default interface */
 		if (is_first_nf) {
 			uk_pr_info("%c%c%u: Set as default interface\n",