From: Roy Marples <roy@marples.name>
Date: Thu, 19 Sep 2019 18:20:16 +0000 (+0100)
Subject: DHCP: Don't request an automatically requested option if not wanted
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=793289f66fa6f4f6d1462fad249d1cc3ae90faf2;p=thirdparty%2Fdhcpcd.git

DHCP: Don't request an automatically requested option if not wanted

This handy macro also simplifies the logic a little.
---

diff --git a/src/dhcp-common.h b/src/dhcp-common.h
index 2732823a..a711a184 100644
--- a/src/dhcp-common.h
+++ b/src/dhcp-common.h
@@ -81,6 +81,11 @@
 #define	OT_BITFLAG		(1 << 27)
 #define	OT_RESERVED		(1 << 28)
 
+#define DHC_REQOPT(o, r, n)						  \
+	(!((o)->type & OT_NOREQ) &&					  \
+	 ((o)->type & OT_REQUEST || has_option_mask((r), (o)->option)) && \
+	  !has_option_mask((n), (o)->option))
+
 struct dhcp_opt {
 	uint32_t option; /* Also used for IANA Enterpise Number */
 	int type;
diff --git a/src/dhcp.c b/src/dhcp.c
index 75eb3f56..fc21904b 100644
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -1032,10 +1032,7 @@ make_message(struct bootp **bootpm, const struct interface *ifp, uint8_t type)
 		    i < ifp->ctx->dhcp_opts_len;
 		    i++, opt++)
 		{
-			if (!(opt->type & OT_REQUEST ||
-			    has_option_mask(ifo->requestmask, opt->option)))
-				continue;
-			if (opt->type & OT_NOREQ)
+			if (!DHC_REQOPT(opt, ifo->requestmask, ifo->nomask))
 				continue;
 			if (type == DHCP_INFORM &&
 			    (opt->option == DHO_RENEWALTIME ||
@@ -1054,10 +1051,7 @@ make_message(struct bootp **bootpm, const struct interface *ifp, uint8_t type)
 					break;
 			if (lp < p)
 				continue;
-			if (!(opt->type & OT_REQUEST ||
-			    has_option_mask(ifo->requestmask, opt->option)))
-				continue;
-			if (opt->type & OT_NOREQ)
+			if (!DHC_REQOPT(opt, ifo->requestmask, ifo->nomask))
 				continue;
 			if (type == DHCP_INFORM &&
 			    (opt->option == DHO_RENEWALTIME ||
diff --git a/src/dhcp6.c b/src/dhcp6.c
index 3c22005c..08183370 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -680,27 +680,21 @@ dhcp6_makemessage(struct interface *ifp)
 					break;
 			}
 			if (n < ifo->dhcp6_override_len)
-			    continue;
-			if (!(opt->type & OT_NOREQ) &&
-			    (opt->type & OT_REQUEST ||
-			    has_option_mask(ifo->requestmask6, opt->option)))
-			{
-				n_options++;
-				len += sizeof(o.len);
-			}
+				continue;
+			if (!DHC_REQOPT(opt, ifo->requestmask6, ifo->nomask6))
+				continue;
+			n_options++;
+			len += sizeof(o.len);
 		}
 #ifndef SMALL
 		for (l = 0, opt = ifo->dhcp6_override;
 		    l < ifo->dhcp6_override_len;
 		    l++, opt++)
 		{
-			if (!(opt->type & OT_NOREQ) &&
-			    (opt->type & OT_REQUEST ||
-			    has_option_mask(ifo->requestmask6, opt->option)))
-			{
-				n_options++;
-				len += sizeof(o.len);
-			}
+			if (!DHC_REQOPT(opt, ifo->requestmask6, ifo->nomask6))
+				continue;
+			n_options++;
+			len += sizeof(o.len);
 		}
 		if (dhcp6_findselfsla(ifp)) {
 			n_options++;
@@ -1060,34 +1054,26 @@ dhcp6_makemessage(struct interface *ifp)
 				if (n < ifo->dhcp6_override_len)
 				    continue;
 #endif
-				if (!(opt->type & OT_NOREQ) &&
-				    (opt->type & OT_REQUEST ||
-				    has_option_mask(ifo->requestmask6,
-				        opt->option)))
-				{
-					o.code = htons((uint16_t)opt->option);
-					memcpy(p, &o.code, sizeof(o.code));
-					p += sizeof(o.code);
-					o.len = (uint16_t)
-					    (o.len + sizeof(o.code));
-				}
+				if (!DHC_REQOPT(opt, ifo->requestmask6,
+				    ifo->nomask6))
+					continue;
+				o.code = htons((uint16_t)opt->option);
+				memcpy(p, &o.code, sizeof(o.code));
+				p += sizeof(o.code);
+				o.len = (uint16_t)(o.len + sizeof(o.code));
 			}
 #ifndef SMALL
 			for (l = 0, opt = ifo->dhcp6_override;
 			    l < ifo->dhcp6_override_len;
 			    l++, opt++)
 			{
-				if (!(opt->type & OT_NOREQ) &&
-				    (opt->type & OT_REQUEST ||
-				    has_option_mask(ifo->requestmask6,
-				        opt->option)))
-				{
-					o.code = htons((uint16_t)opt->option);
-					memcpy(p, &o.code, sizeof(o.code));
-					p += sizeof(o.code);
-					o.len = (uint16_t)
-					    (o.len + sizeof(o.code));
-				}
+				if (!DHC_REQOPT(opt, ifo->requestmask6,
+				    ifo->nomask6))
+					continue;
+				o.code = htons((uint16_t)opt->option);
+				memcpy(p, &o.code, sizeof(o.code));
+				p += sizeof(o.code);
+				o.len = (uint16_t)(o.len + sizeof(o.code));
 			}
 			if (dhcp6_findselfsla(ifp)) {
 				o.code = htons(D6_OPTION_PD_EXCLUDE);