busybox: add SRV support to nslookup_lede.c patch

Add support for querying and parsing SRV DNS records to nslookup_lede.c

This patch is based on http://lists.busybox.net/pipermail/busybox/2019-June/087359.html

Signed-off-by: Perry Melange <[email protected]>
[reword subject, bump PKG_RELEASE]
Signed-off-by: Paul Spooren <[email protected]>

package/utils/busybox/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=busybox
 PKG_VERSION:=1.33.0
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 PKG_FLAGS:=essential
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2

package/utils/busybox/patches/230-add_nslookup_lede.patch

@@ -34,7 +34,7 @@ Signed-off-by: Jo-Philipp Wich <[email protected]>
  # However, on *other platforms* it fails when some of those flags
 --- /dev/null
 +++ b/networking/nslookup_lede.c
-@@ -0,0 +1,914 @@
+@@ -0,0 +1,934 @@
 +/*
 + * nslookup_lede - musl compatible replacement for busybox nslookup
 + *
@@ -128,6 +128,7 @@ Signed-off-by: Jo-Philipp Wich <[email protected]>
 +	{ ns_t_cname, "CNAME" },
 +	{ ns_t_mx,    "MX"    },
 +	{ ns_t_txt,   "TXT"   },
++	{ ns_t_srv,   "SRV"   },
 +	{ ns_t_ptr,   "PTR"   },
 +	{ ns_t_any,   "ANY"   },
 +	{ }
@@ -259,6 +260,25 @@ Signed-off-by: Jo-Philipp Wich <[email protected]>
 +			}
 +			break;
 +
++		case ns_t_srv:
++			if (rdlen < 6) {
++				//printf("SRV record too short\n");
++				return -1;
++			}
++
++			cp = ns_rr_rdata(rr);
++			n = ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle),
++			                       cp + 6, dname, sizeof(dname));
++
++			if (n < 0) {
++				//printf("Unable to uncompress domain: %s\n", strerror(errno));
++				return -1;
++			}
++
++			printf("%s\tservice = %hu %hu %hu %s\n", ns_rr_name(rr),
++				ns_get16(cp), ns_get16(cp + 2), ns_get16(cp + 4), dname);
++			break;
++
 +		case ns_t_soa:
 +			if (rdlen < 20) {
 +				//fprintf(stderr, "SOA record too short\n");