From: Roy Marples <roy@marples.name>
Date: Fri, 2 Sep 2016 11:34:09 +0000 (+0000)
Subject: Remove the need for statically sized receive buffers for IPv6 ND and DHCPv6
X-Git-Tag: v6.11.4~59
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2629170f018b01ab126451c89cfbf9a37b9b8fc7;p=thirdparty%2Fdhcpcd.git

Remove the need for statically sized receive buffers for IPv6 ND and DHCPv6
messages.
---

diff --git a/dhcp6.c b/dhcp6.c
index 7b3935cc..5f183e56 100644
--- a/dhcp6.c
+++ b/dhcp6.c
@@ -2647,7 +2647,7 @@ dhcp6_handledata(void *arg)
 	dctx = arg;
 	ctx = dctx->ipv6;
 	ctx->rcvhdr.msg_controllen = CMSG_SPACE(sizeof(struct in6_pktinfo));
-	bytes = recvmsg(ctx->dhcp_fd, &ctx->rcvhdr, 0);
+	bytes = recvmsg_realloc(ctx->dhcp_fd, &ctx->rcvhdr, 0);
 	if (bytes == -1) {
 		logger(dctx, LOG_ERR, "%s: recvmsg: %m", __func__);
 		close(ctx->dhcp_fd);
diff --git a/ipv6.c b/ipv6.c
index 2cd45be4..35ff4f79 100644
--- a/ipv6.c
+++ b/ipv6.c
@@ -154,19 +154,17 @@ ipv6_init(struct dhcpcd_ctx *dhcpcd_ctx)
 	TAILQ_INIT(&ctx->kroutes);
 
 	ctx->sndhdr.msg_namelen = sizeof(struct sockaddr_in6);
-	ctx->sndhdr.msg_iov = ctx->sndiov;
+	ctx->sndhdr.msg_iov = &ctx->sndiov;
 	ctx->sndhdr.msg_iovlen = 1;
 	ctx->sndhdr.msg_control = ctx->sndbuf;
 	ctx->sndhdr.msg_controllen = sizeof(ctx->sndbuf);
 	ctx->rcvhdr.msg_name = &ctx->from;
 	ctx->rcvhdr.msg_namelen = sizeof(ctx->from);
-	ctx->rcvhdr.msg_iov = ctx->rcviov;
+	ctx->rcvhdr.msg_iov = &dhcpcd_ctx->iov;
 	ctx->rcvhdr.msg_iovlen = 1;
-	ctx->rcvhdr.msg_control = ctx->rcvbuf;
+	ctx->rcvhdr.msg_control = ctx->ctlbuf;
 	// controllen is set at recieve
 	//ctx->rcvhdr.msg_controllen = sizeof(ctx->rcvbuf);
-	ctx->rcviov[0].iov_base = ctx->ansbuf;
-	ctx->rcviov[0].iov_len = sizeof(ctx->ansbuf);
 
 	ctx->nd_fd = -1;
 	ctx->dhcp_fd = -1;
diff --git a/ipv6.h b/ipv6.h
index b433c016..4a1248b9 100644
--- a/ipv6.h
+++ b/ipv6.h
@@ -260,17 +260,14 @@ struct ipv6_state {
 #define IP6BUFLEN	(CMSG_SPACE(sizeof(struct in6_pktinfo)) + \
 			CMSG_SPACE(sizeof(int)))
 
-
 #ifdef INET6
 struct ipv6_ctx {
+	unsigned char ctlbuf[IP6BUFLEN];
 	struct sockaddr_in6 from;
 	struct msghdr sndhdr;
-	struct iovec sndiov[2];
+	struct iovec sndiov;
 	unsigned char sndbuf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 	struct msghdr rcvhdr;
-	struct iovec rcviov[2];
-	unsigned char rcvbuf[IP6BUFLEN];
-	unsigned char ansbuf[1500];
 	char ntopbuf[INET6_ADDRSTRLEN];
 	const char *sfrom;
 
diff --git a/ipv6nd.c b/ipv6nd.c
index 71075002..11415c1f 100644
--- a/ipv6nd.c
+++ b/ipv6nd.c
@@ -1551,7 +1551,7 @@ ipv6nd_handledata(void *arg)
 	ctx = dctx->ipv6;
 	ctx->rcvhdr.msg_controllen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
 	    CMSG_SPACE(sizeof(int));
-	len = recvmsg(ctx->nd_fd, &ctx->rcvhdr, 0);
+	len = recvmsg_realloc(ctx->nd_fd, &ctx->rcvhdr, 0);
 	if (len == -1) {
 		logger(dctx, LOG_ERR, "recvmsg: %m");
 		eloop_event_delete(dctx->eloop, ctx->nd_fd);