From: Roy Marples <roy@marples.name>
Date: Tue, 19 Feb 2019 21:46:06 +0000 (+0000)
Subject: Fold all CMSG parsing into a common function.
X-Git-Tag: v7.2.0~31
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0ac6d9c9ebb8e179a1887181527e3684beb17df0;p=thirdparty%2Fdhcpcd.git

Fold all CMSG parsing into a common function.

Makes dhcpcd smaller still.
---

diff --git a/src/dhcp.c b/src/dhcp.c
index 4a8f5d57..fb916700 100644
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -3477,36 +3477,9 @@ dhcp_readudp(struct dhcpcd_ctx *ctx, struct interface *ifp)
 	inet_ntop(AF_INET, &from.sin_addr, sfrom, sizeof(sfrom));
 
 	if (ifp == NULL) {
-		struct cmsghdr *cm;
-		struct in_pktinfo pi;
-
-		pi.ipi_ifindex = 0;
-		for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&msg);
-		    cm;
-		    cm = (struct cmsghdr *)CMSG_NXTHDR(&msg, cm))
-		{
-			if (cm->cmsg_level != IPPROTO_IP)
-				continue;
-			switch(cm->cmsg_type) {
-			case IP_PKTINFO:
-				if (cm->cmsg_len == CMSG_LEN(sizeof(pi)))
-					memcpy(&pi, CMSG_DATA(cm), sizeof(pi));
-				break;
-			}
-		}
-		if (pi.ipi_ifindex == 0) {
-			logerrx("DHCP reply did not contain index from %s",
-			    sfrom);
-			return;
-		}
-
-		TAILQ_FOREACH(ifp, ctx->ifaces, next) {
-			if (ifp->index == (unsigned int)pi.ipi_ifindex)
-				break;
-		}
+		ifp = if_findifpfromcmsg(ctx, &msg, NULL);
 		if (ifp == NULL) {
-			logerrx("DHCP reply for unexpected interface from %s",
-			    sfrom);
+			logerr(__func__);
 			return;
 		}
 	}
diff --git a/src/dhcp6.c b/src/dhcp6.c
index c50efb66..6e83a70f 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -3498,36 +3498,9 @@ dhcp6_recv(struct dhcpcd_ctx *ctx, struct ipv6_addr *ia)
 	if (ia != NULL)
 		ifp = ia->iface;
 	else {
-		struct cmsghdr *cm;
-		struct in6_pktinfo pi;
-
-		pi.ipi6_ifindex = 0;
-		for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&msg);
-		    cm;
-		    cm = (struct cmsghdr *)CMSG_NXTHDR(&msg, cm))
-		{
-			if (cm->cmsg_level != IPPROTO_IPV6)
-				continue;
-			switch(cm->cmsg_type) {
-			case IPV6_PKTINFO:
-				if (cm->cmsg_len == CMSG_LEN(sizeof(pi)))
-					memcpy(&pi, CMSG_DATA(cm), sizeof(pi));
-				break;
-			}
-		}
-		if (pi.ipi6_ifindex == 0) {
-			logerrx("DHCPv6 reply did not contain index from %s",
-			    sfrom);
-			return;
-		}
-
-		TAILQ_FOREACH(ifp, ctx->ifaces, next) {
-			if (ifp->index == (unsigned int)pi.ipi6_ifindex)
-				break;
-		}
+		ifp = if_findifpfromcmsg(ctx, &msg, NULL);
 		if (ifp == NULL) {
-			logerrx("DHCPv6 reply for unexpected interface from %s",
-			    sfrom);
+			logerr(__func__);
 			return;
 		}
 	}
diff --git a/src/if.c b/src/if.c
index 42b3e7b3..9ba286d1 100644
--- a/src/if.c
+++ b/src/if.c
@@ -801,6 +801,68 @@ if_sortinterfaces(struct dhcpcd_ctx *ctx)
 	TAILQ_CONCAT(ctx->ifaces, &sorted, next);
 }
 
+struct interface *
+if_findifpfromcmsg(struct dhcpcd_ctx *ctx, struct msghdr *msg, int *hoplimit)
+{
+	struct cmsghdr *cm;
+	unsigned int ifindex = 0;
+	struct interface *ifp;
+#ifdef INET
+	struct in_pktinfo ipi;
+#endif
+#ifdef INET6
+	struct in6_pktinfo ipi6;
+#else
+	UNUSED(hoplimit);
+#endif
+
+	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(msg);
+	     cm;
+	     cm = (struct cmsghdr *)CMSG_NXTHDR(msg, cm))
+	{
+#ifdef INET
+		if (cm->cmsg_level == IPPROTO_IP) {
+			switch(cm->cmsg_type) {
+			case IP_PKTINFO:
+				if (cm->cmsg_len != CMSG_LEN(sizeof(ipi)))
+					continue;
+				memcpy(&ipi, CMSG_DATA(cm), sizeof(ipi));
+				ifindex = (unsigned int)ipi.ipi_ifindex;
+				break;
+			}
+		}
+#endif
+#ifdef INET6
+		if (cm->cmsg_level == IPPROTO_IPV6) {
+			switch(cm->cmsg_type) {
+			case IPV6_PKTINFO:
+				if (cm->cmsg_len != CMSG_LEN(sizeof(ipi6)))
+					continue;
+				memcpy(&ipi6, CMSG_DATA(cm), sizeof(ipi6));
+				ifindex = (unsigned int)ipi6.ipi6_ifindex;
+				break;
+			case IPV6_HOPLIMIT:
+				if (cm->cmsg_len != CMSG_LEN(sizeof(int)))
+					continue;
+				if (hoplimit == NULL)
+					break;
+				memcpy(hoplimit, CMSG_DATA(cm), sizeof(int));
+				break;
+			}
+		}
+#endif
+	}
+
+	/* Find the receiving interface */
+	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
+		if (ifp->index == ifindex)
+			break;
+	}
+	if (ifp == NULL)
+		errno = ESRCH;
+	return ifp;
+}
+
 int
 xsocket(int domain, int type, int protocol)
 {
diff --git a/src/if.h b/src/if.h
index d260d2d1..2f20764c 100644
--- a/src/if.h
+++ b/src/if.h
@@ -209,5 +209,7 @@ int if_getlifetime6(struct ipv6_addr *);
 #endif
 
 int if_machinearch(char *, size_t);
+struct interface *if_findifpfromcmsg(struct dhcpcd_ctx *,
+    struct msghdr *, int *);
 int xsocket(int, int, int);
 #endif
diff --git a/src/ipv6nd.c b/src/ipv6nd.c
index 7f67287c..bef77b2a 100644
--- a/src/ipv6nd.c
+++ b/src/ipv6nd.c
@@ -1672,10 +1672,8 @@ ipv6nd_handledata(void *arg)
 	    .msg_control = ctl, .msg_controllen = sizeof(ctl),
 	};
 	ssize_t len;
-	struct cmsghdr *cm;
 	char sfrom[INET6_ADDRSTRLEN];
-	int hoplimit;
-	struct in6_pktinfo pkt;
+	int hoplimit = 0;
 	struct icmp6_hdr *icp;
 	struct interface *ifp;
 
@@ -1691,41 +1689,15 @@ ipv6nd_handledata(void *arg)
 		return;
 	}
 
-	pkt.ipi6_ifindex = 0;
-	hoplimit = 0;
-	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&msg);
-	     cm;
-	     cm = (struct cmsghdr *)CMSG_NXTHDR(&msg, cm))
-	{
-		if (cm->cmsg_level != IPPROTO_IPV6)
-			continue;
-		switch(cm->cmsg_type) {
-		case IPV6_PKTINFO:
-			if (cm->cmsg_len == CMSG_LEN(sizeof(pkt)))
-				memcpy(&pkt, CMSG_DATA(cm), sizeof(pkt));
-			break;
-		case IPV6_HOPLIMIT:
-			if (cm->cmsg_len == CMSG_LEN(sizeof(int)))
-				memcpy(&hoplimit, CMSG_DATA(cm), sizeof(int));
-			break;
-		}
-	}
-
-	if (pkt.ipi6_ifindex == 0) {
-		logerrx("IPv6 RA/NA did not contain index from %s", sfrom);
+	ifp = if_findifpfromcmsg(ctx, &msg, &hoplimit);
+	if (ifp == NULL) {
+		logerr(__func__);
 		return;
 	}
 
-	/* Find the receiving interface */
-	TAILQ_FOREACH(ifp, ctx->ifaces, next) {
-		if (ifp->index == (unsigned int)pkt.ipi6_ifindex)
-			break;
-	}
-
 	/* Don't do anything if the user hasn't configured it. */
-	if (ifp != NULL &&
-	    (ifp->active != IF_ACTIVE_USER ||
-	    !(ifp->options->options & DHCPCD_IPV6)))
+	if (ifp->active != IF_ACTIVE_USER ||
+	    !(ifp->options->options & DHCPCD_IPV6))
 		return;
 
 	icp = (struct icmp6_hdr *)buf;