From: Shawn Routhier <sar@isc.org>
Date: Wed, 15 Apr 2015 19:46:52 +0000 (-0700)
Subject: [master] Expand use of #ifdef PACKET_AUXDATA to cover allocating cmsgbuf
X-Git-Tag: v4_3_3b1~31
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1c0b7d66b67f85c96f62d94896ad6403fffc79dc;p=thirdparty%2Fdhcp.git

[master] Expand use of #ifdef PACKET_AUXDATA to cover allocating cmsgbuf

Most of the use of tpacket_auxdata was alredy protected by PACKET_AUXDATA
this patch covers trying to find the proper size for the cmsgbuf.
---

diff --git a/RELNOTES b/RELNOTES
index ac4e2aee5..4050e3599 100644
--- a/RELNOTES
+++ b/RELNOTES
@@ -82,6 +82,12 @@ by Eric Young (eay@cryptsoft.com).
   The new configuration option is "./configure --with-atf=bind".
   [ISC-Bugs #38754]
 
+- Corrected a compilation error introduced by the fix for ISC-Bugs #22806.
+  On older linuxes that do not include the tpacket_auxdata structure don't
+  bother allocating the cmsgbuf as it isn't necessary and we don't have
+  a proper length for it.
+  [ISC-Bugs #39209]
+
 			Changes since 4.3.2rc2
 - None
 
diff --git a/common/lpf.c b/common/lpf.c
index cd430dd76..7889b6bbf 100644
--- a/common/lpf.c
+++ b/common/lpf.c
@@ -368,17 +368,30 @@ ssize_t receive_packet (interface, buf, len, from, hfrom)
 	unsigned char ibuf [1536];
 	unsigned bufix = 0;
 	unsigned paylen;
-	unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
 	struct iovec iov = {
 		.iov_base = ibuf,
 		.iov_len = sizeof ibuf,
 	};
+#ifdef PACKET_AUXDATA
+	/*
+	 * We only need cmsgbuf if we are getting the aux data and we
+	 * only get the auxdata if it is actually defined
+	 */
+	unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
 	struct msghdr msg = {
 		.msg_iov = &iov,
 		.msg_iovlen = 1,
 		.msg_control = cmsgbuf,
 		.msg_controllen = sizeof(cmsgbuf),
 	};
+#else
+	struct msghdr msg = {
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = NULL,
+		.msg_controllen = 0,
+	};
+#endif /* PACKET_AUXDATA */
 
 	length = recvmsg (interface->rfdesc, &msg, 0);
 	if (length <= 0)
@@ -422,7 +435,7 @@ ssize_t receive_packet (interface, buf, len, from, hfrom)
 	}
 
 	}
-#endif
+#endif /* PACKET_AUXDATA */
 
 	bufix = 0;
 	/* Decode the physical header... */