From: Roy Marples <roy@marples.name>
Date: Fri, 2 Sep 2016 08:09:47 +0000 (+0000)
Subject: Rework the recvmsg_realloc function to handle flags.
X-Git-Tag: v6.11.4~64
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c62f687eb8edf0eafca1aeed8c9241ee4a3f4797;p=thirdparty%2Fdhcpcd.git

Rework the recvmsg_realloc function to handle flags.

Commit also includes mistakenly added ifam_pid patch for BSD.
It does no harm being here, even though no BSD supports this yet.
---

diff --git a/common.c b/common.c
index 3c0de44e..9b62a6a5 100644
--- a/common.c
+++ b/common.c
@@ -397,21 +397,19 @@ iovec_realloc(struct iovec *iov, size_t size)
 }
 
 ssize_t
-recvmsg_alloc(int fd, struct msghdr *msg)
+recvmsg_realloc(int fd, struct msghdr *msg, int flags)
 {
 	ssize_t bytes;
 
-	if (msg->msg_iovlen == 0)
-		msg->msg_iovlen = 1;
-
 	for (;;) {
-		msg->msg_flags &= ~MSG_TRUNC;
-		if ((bytes = recvmsg(fd, msg, MSG_PEEK | MSG_TRUNC)) == -1)
+		msg->msg_flags = 0;
+		bytes = recvmsg(fd, msg, flags | MSG_PEEK | MSG_TRUNC);
+		if (bytes == -1)
 			return -1;
 		if (!(msg->msg_flags & MSG_TRUNC))
 			break;
 
-		/* Some buggy kernels return the truncated size. */
+		/* Some kernels return the truncated size. */
 		if (msg->msg_iov->iov_len == (size_t)bytes) {
 			size_t nl;
 
@@ -425,6 +423,6 @@ recvmsg_alloc(int fd, struct msghdr *msg)
 		}
 	}
 
-	bytes = recvmsg(fd, msg, 0);
+	bytes = recvmsg(fd, msg, flags);
 	return msg->msg_flags & MSG_TRUNC ? -1 : bytes;
 }
diff --git a/common.h b/common.h
index 38924bc3..da9aea96 100644
--- a/common.h
+++ b/common.h
@@ -197,5 +197,5 @@ char *hwaddr_ntoa(const uint8_t *, size_t, char *, size_t);
 size_t hwaddr_aton(uint8_t *, const char *);
 size_t read_hwaddr_aton(uint8_t **, const char *);
 
-ssize_t recvmsg_alloc(int fd, struct msghdr *msg);
+ssize_t recvmsg_realloc(int, struct msghdr *, int);
 #endif
diff --git a/configure b/configure
index 0f22c869..a6ed2f29 100755
--- a/configure
+++ b/configure
@@ -506,7 +506,22 @@ EOF
 		echo "no"
 	fi
 	rm -f _IN6_ADDR_GEN_MODE_NONE.c _IN6_ADDR_GEN_MODE_NONE
-
+else
+	printf "Testing for ifam_pid ... "
+	cat <<EOF >_ifam_pid.c
+#include <net/if.h>
+int main(void) {
+	struct ifa_msghdr ifam = { };
+	return (int)ifam.ifam_pid;
+}
+EOF
+	if $XCC _ifam_pid.c -o _ifam_pid 2>&3; then
+		echo "yes"
+		echo "#define HAVE_IFAM_PID" >>$CONFIG_H
+	else
+		echo "no"
+	fi
+	rm -f _ifam_pid.c _ifam_pid
 fi
 
 abort=false
diff --git a/if-bsd.c b/if-bsd.c
index fbcb5172..7bc54e09 100644
--- a/if-bsd.c
+++ b/if-bsd.c
@@ -1312,32 +1312,43 @@ if_ifinfo(struct dhcpcd_ctx *ctx, const struct if_msghdr *ifm)
 	    (unsigned int)ifm->ifm_flags, ifp->name);
 }
 
-static void
-if_rtm(struct dhcpcd_ctx *ctx, const struct rt_msghdr *rtm)
+static int
+if_ownmsgpid(struct dhcpcd_ctx *ctx, pid_t pid, int seq)
 {
-	const struct sockaddr *sa;
 
 	/* Ignore messages generated by us */
-	if (rtm->rtm_pid == getpid()) {
+	if (getpid() == pid) {
 		ctx->options &= ~DHCPCD_RTM_PPID;
-		return;
+		return 1;
 	}
 
 	/* Ignore messages sent by the parent after forking */
 	if ((ctx->options &
 	    (DHCPCD_RTM_PPID | DHCPCD_DAEMONISED)) ==
 	    (DHCPCD_RTM_PPID | DHCPCD_DAEMONISED) &&
-	    rtm->rtm_pid == ctx->ppid)
+	    ctx->ppid == pid)
 	{
 		/* If this is the last successful message sent,
 		 * clear the check flag as it's possible another
 		 * process could re-use the same pid and also
-		 * manipulate therouting table. */
-		if (rtm->rtm_seq == ctx->pseq)
+		 * manipulate the routing table. */
+		if (ctx->pseq == seq)
 			ctx->options &= ~DHCPCD_RTM_PPID;
-		return;
+		return 1;
 	}
 
+	/* Not a message we made. */
+	return 0;
+}
+
+static void
+if_rtm(struct dhcpcd_ctx *ctx, const struct rt_msghdr *rtm)
+{
+	const struct sockaddr *sa;
+
+	if (if_ownmsgpid(ctx, rtm->rtm_pid, rtm->rtm_seq))
+		return;
+
 	sa = (const void *)(rtm + 1);
 	switch (sa->sa_family) {
 #ifdef INET
@@ -1395,9 +1406,11 @@ if_ifa(struct dhcpcd_ctx *ctx, const struct ifa_msghdr *ifam)
 	struct interface *ifp;
 	const struct sockaddr *rti_info[RTAX_MAX];
 
-	/* XXX We have no way of knowing who generated these
-	 * messages wich truely sucks because we want to
-	 * avoid listening to our own delete messages. */
+#ifdef HAVE_IFAM_PID
+	if (if_ownmsgpid(ctx, ifam->ifam_pid, 0))
+		return;
+#endif
+
 	if ((ifp = if_findindex(ctx->ifaces, ifam->ifam_index)) == NULL)
 		return;
 	get_addrs(ifam->ifam_addrs, ifam + 1, rti_info);
@@ -1521,8 +1534,9 @@ if_handlelink(struct dhcpcd_ctx *ctx)
 
 	memset(&msg, 0, sizeof(msg));
 	msg.msg_iov = &ctx->iov;
+	msg.msg_iovlen = 1;
 
-	if ((bytes = recvmsg_alloc(ctx->link_fd, &msg)) == -1)
+	if ((bytes = recvmsg_realloc(ctx->link_fd, &msg, 0)) == -1)
 		return -1;
 	if_dispatch(ctx, ctx->iov.iov_base);
 	return 0;
diff --git a/if-linux.c b/if-linux.c
index 9d379193..c247b101 100644
--- a/if-linux.c
+++ b/if-linux.c
@@ -344,12 +344,12 @@ get_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp, int fd, int flags,
 	int r;
 
 	memset(&msg, 0, sizeof(msg));
-	msg.msg_flags = flags;
 	msg.msg_name = &nladdr;
 	msg.msg_namelen = sizeof(nladdr);
 	memset(&nladdr, 0, sizeof(nladdr));
 	msg.msg_iov = &ctx->iov;
-	if ((bytes = recvmsg_alloc(fd, &msg)) == -1)
+	msg.msg_iovlen = 1;
+	if ((bytes = recvmsg_realloc(fd, &msg, flags)) == -1)
 		return -1;
 
 	/* Check sender */
diff --git a/if-sun.c b/if-sun.c
index 064ab936..8ce1887b 100644
--- a/if-sun.c
+++ b/if-sun.c
@@ -774,8 +774,9 @@ if_handlelink(struct dhcpcd_ctx *ctx)
 
 	memset(&msg, 0, sizeof(msg));
 	msg.msg_iov = &ctx->iov;
+	msg.msg_iovlen = 1;
 
-	if ((bytes = recvmsg_alloc(ctx->link_fd, &msg)) == -1)
+	if ((bytes = recvmsg_realloc(ctx->link_fd, &msg, 0)) == -1)
 		return -1;
 	if_dispatch(ctx, ctx->iov.iov_base);
 	return 0;