From: Roy Marples <roy@marples.name>
Date: Fri, 6 May 2016 13:02:41 +0000 (+0000)
Subject: Move dhcp6's read lease code into dhcp-common.
X-Git-Tag: v6.11.0~22
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=416a319e23031e0dff2d5c5f95d73ddcde052cd4;p=thirdparty%2Fdhcpcd.git

Move dhcp6's read lease code into dhcp-common.
While here, fix MTU min/max.
---

diff --git a/dhcp-common.c b/dhcp-common.c
index d8028ce7..74336fd6 100644
--- a/dhcp-common.c
+++ b/dhcp-common.c
@@ -1056,3 +1056,39 @@ dhcp_zero_index(struct dhcp_opt *opt)
 	for (i = 0, o = opt->encopts; i < opt->encopts_len; i++, o++)
 		dhcp_zero_index(o);
 }
+
+size_t
+dhcp_read_lease_fd(int fd, uint8_t **lease)
+{
+	uint8_t *buf, *nbuf;
+	size_t len, new_len;
+	ssize_t bytes;
+
+	if ((buf = malloc(BUFSIZ)) == NULL)
+		goto out;
+
+	len = 0;
+	for (;;) {
+		bytes = read(fd, buf + len, BUFSIZ);
+		if (bytes == -1)
+			break;
+		if (bytes < BUFSIZ) {
+			*lease = buf;
+			return len + (size_t)bytes;
+		}
+		new_len = len + (BUFSIZ * 2);
+		if (new_len > UINT32_MAX || new_len < len) {
+			errno = E2BIG;
+			break;
+		}
+		if ((nbuf = realloc(buf, new_len)) == NULL)
+			break;
+		buf = nbuf;
+		len += BUFSIZ;
+	}
+
+	free(buf);
+out:
+	*lease = NULL;
+	return 0;
+}
diff --git a/dhcp-common.h b/dhcp-common.h
index f576a172..61eccf18 100644
--- a/dhcp-common.h
+++ b/dhcp-common.h
@@ -37,8 +37,9 @@
 #include "dhcpcd.h"
 
 /* Max MTU - defines dhcp option length */
-#define	MTU_MAX			1500
-#define	MTU_MIN			 576
+#define	IP_UDP_SIZE		  28
+#define	MTU_MAX			1500 - IP_UDP_SIZE
+#define	MTU_MIN			 576 + IP_UDP_SIZE
 
 #define	OT_REQUEST		(1 << 0)
 #define	OT_UINT8		(1 << 1)
@@ -117,5 +118,6 @@ size_t dhcp_envoption(struct dhcpcd_ctx *,
     const uint8_t *, size_t, struct dhcp_opt **),
     const uint8_t *od, size_t ol);
 void dhcp_zero_index(struct dhcp_opt *);
+size_t dhcp_read_lease_fd(int, uint8_t **);
 
 #endif
diff --git a/dhcp6.c b/dhcp6.c
index d5457e37..3c1f060f 100644
--- a/dhcp6.c
+++ b/dhcp6.c
@@ -2162,18 +2162,16 @@ dhcp6_readlease(struct interface *ifp, int validate)
 	struct dhcp6_state *state;
 	struct stat st;
 	int fd;
-	ssize_t bytes;
+	uint8_t *lease;
 	const struct dhcp6_option *o;
 	struct timespec acquired;
 	time_t now;
 	int retval;
-	size_t newlen;
-	void *newnew;
 	bool fd_opened;
 
 	state = D6_STATE(ifp);
 	if (state->leasefile[0] == '\0') {
- 		logger(ifp->ctx, LOG_DEBUG, "reading standard input");
+		logger(ifp->ctx, LOG_DEBUG, "reading standard input");
 		fd = fileno(stdin);
 		fd_opened = false;
 	} else {
@@ -2188,39 +2186,13 @@ dhcp6_readlease(struct interface *ifp, int validate)
 	}
 	if (fd == -1)
 		return -1;
-	state->new_len = 0;
-	if ((state->new = malloc(BUFSIZ)) == NULL) {
-		if (fd_opened)
-			close(fd);
-		return -1;
-	}
 	retval = -1;
-	/* DHCPv6 messages have no real maximum size.
-	 * As we could be reading from stdin, we loop like so.
-	 * state->new_len refers to the buffer position,
-	 * but the buffer itself always BUFSIZ bigger. */
-	for (;;) {
-		bytes = read(fd, (char *)state->new + state->new_len, BUFSIZ);
-		if (bytes == -1)
-			break;
-		if (bytes < BUFSIZ) {
-			state->new_len += (size_t)bytes;
-			retval = 0;
-			break;
-		}
-		newlen = state->new_len + (BUFSIZ * 2);
-		if (newlen > UINT32_MAX || newlen < state->new_len) {
-			errno = E2BIG;
-			break;
-		}
-		if ((newnew = realloc(state->new, newlen)) == NULL)
-			break;
-		state->new = newnew;
-		state->new_len += BUFSIZ;
-	}
+	lease = NULL;
+	state->new_len = dhcp_read_lease_fd(fd, &lease);
+	state->new = (struct dhcp6_message *)lease;
 	if (fd_opened)
 		close(fd);
-	if (retval == -1)
+	if (state->new_len == 0)
 		goto ex;
 
 	if (ifp->ctx->options & DHCPCD_DUMPLEASE ||
@@ -2234,7 +2206,6 @@ dhcp6_readlease(struct interface *ifp, int validate)
 		goto auth;
 	}
 
-	retval = -1;
 	clock_gettime(CLOCK_MONOTONIC, &acquired);
 	if ((now = time(NULL)) == -1)
 		goto ex;