PPP enhanced ifname

pppd/main.c

@@ -70,6 +70,7 @@
 #include <ctype.h>
 #include <stdlib.h>
 #include <string.h>
+#include <regex.h>
 #include <unistd.h>
 #include <signal.h>
 #include <errno.h>
@@ -87,6 +88,7 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
+#include <net/if.h>
 
 #include "pppd.h"
 #include "magic.h"
@@ -728,10 +730,73 @@ set_ifunit(int iskey)
 {
     char ifkey[32];
 
+    char ifnameBase[IFNAMSIZ];
+
+    memset(ifnameBase, '\0', sizeof(ifnameBase));
+    memset(ifname, '\0', sizeof(ifname));
+
+    // Variable to create regex
+    regex_t *regex;
+
+    regex = malloc(sizeof(regex_t));
+
+    size_t     nmatch = 2;
+    regmatch_t pmatch[2];
+
+    // We need at least one character in the front of the ifunit
+    char *pattern = ".+(%d)";
+
+    int rc = 0;
+
+    // If we are requesting a specific name via "ifname" parameter, we have to check if is static or we have to include the ifunit in the name.
     if (req_ifname[0] != '\0')
-	slprintf(ifname, sizeof(ifname), "%s", req_ifname);
+    {
+
+#ifdef __linux__
+	// Compile and create the regex
+	rc = regcomp(regex, pattern, REG_EXTENDED);
+
+	if (rc != 0) {
+	    slprintf(ifname, sizeof(ifname), "%s%d", PPP_DRV_NAME, ifunit);
+	    warn("Warning: couldn't compile the regex \"%s\". Fallback to %s format.", pattern, ifname);
+	    goto set_ifunit_regex_done;
+	}
+
+	// If the regex compliation is successful we will continue to try to extract the interface base name.
+	if ((rc = regexec(regex, req_ifname, nmatch, pmatch, 0)) != 0) {
+	    // If we can't find our regex, means that is using a fixed name.
+	    slprintf(ifname, sizeof(ifname), "%s", req_ifname);
+	    info("Using static interface naming %s", ifname);
+	    goto set_ifunit_regex_done;
+	}
+
+	/* Matching the dynamic name. We need to have no more than IFNAMSIZ - 4 bytes in the name, to have enough room to build the name.
+	   Linux have a maximum of 16 chars allocated for the interfece names, but only 15 are permited.
+	   So we will have 12 chars for name and 3 chars for digits.
+	*/
+	if (pmatch[1].rm_so >= (IFNAMSIZ-4)) {
+	    slprintf(ifname, sizeof(ifname), "%s%d", PPP_DRV_NAME, ifunit);
+	    warn("Warning: interface base name is too long! Please use up to 12 characters for the name to be able to use at least 3 digits! Fallback to default notation %s", ifname);
+	    goto set_ifunit_regex_done;
+	}
+	else {
+	    // We need to do a small correction in strlcpy when we are mentioning the length of the string: +1
+	    strlcpy(ifnameBase, req_ifname, pmatch[1].rm_so+1);
+	    slprintf(ifname, sizeof(ifname), "%s%d", ifnameBase, ifunit);
+	    info("Found dynamic custom interface naming: %s", ifname);
+	}
+
+set_ifunit_regex_done:
+	// Free regex
+	regfree(regex);
+#else
+	slprintf(ifname, sizeof(ifname), "%s%d", PPP_DRV_NAME, ifunit);
+	info("The option ifname requires Linux. Fallback to %s", ifname);
+#endif
+    }
     else
 	slprintf(ifname, sizeof(ifname), "%s%d", PPP_DRV_NAME, ifunit);
+
     info("Using interface %s", ifname);
     script_setenv("IFNAME", ifname, iskey);
     slprintf(ifkey, sizeof(ifkey), "%d", ifunit);

pppd/options.c

@@ -292,9 +292,8 @@ option_t general_options[] = {
     { "unit", o_int, &req_unit,
       "PPP interface unit number to use if possible",
       OPT_PRIO | OPT_LLIMIT, 0, 0 },
-
     { "ifname", o_string, req_ifname,
-      "Set PPP interface name",
+      "Set PPP interface name. If format is like ppp%%d / pppoe%%d / l2tp%%d, where %%d will be replaced by unit number. Linux Only.",
       OPT_PRIO | OPT_PRIV | OPT_STATIC, NULL, MAXIFNAMELEN },
 
     { "dump", o_bool, &dump_options,

pppd/plugins/radius/radius.c

@@ -40,10 +40,12 @@ static char const RCSID[] =
 #include "ipcp.h"
 #include <syslog.h>
 #include <sys/types.h>
+#include <regex.h>
 #include <sys/time.h>
 #include <string.h>
 #include <netinet/in.h>
 #include <stdlib.h>
+#include <net/if.h>
 
 #define BUF_LEN 1024
 
@@ -1319,9 +1321,88 @@ static int
 get_client_port(char *ifname)
 {
     int port;
-    if (sscanf(ifname, "ppp%d", &port) == 1) {
+    char ifnameBase[IFNAMSIZ]; // in case we have a custom interface naming, we extract the basename here and use in regex
+    char cport[IFNAMSIZ]; // here we have to copy from regex the id of the unit
+
+    regex_t *regex;
+    size_t     nmatch = 2;
+    regmatch_t pmatch[2]; /* Array of matches */
+
+    char pattern[64];
+
+    int rc = 0;
+
+    memset(ifnameBase, '\0', sizeof(ifnameBase));
+    memset(cport, '\0', sizeof(cport));
+    memset(pattern, '\0', sizeof(pattern));
+
+    regex = malloc(sizeof(regex_t));
+
+    /*
+     Let extract the ifnameBase name from the req_ifname.
+     This code will use regex for extracting the ppp unit and it will not be affected by the naming of the interface.
+     We are intereseted to get the number in the end of the interface name.
+     Only one case is special when we are using fix name for the interface, without %d in the end.
+    */
+    if (req_ifname[0] != '\0')
+    {
+
+	strcpy(pattern, ".+(%d)");
+
+	// Compile and create the regex
+	rc = regcomp(regex, pattern, REG_EXTENDED);
+
+	if (rc != 0) {
+	    slprintf(ifnameBase, sizeof(ifnameBase), "%s", PPP_DRV_NAME);
+	    warn("Warning: couldn't compile the regex \"%s\". Fallback to %s%%d format.", pattern, ifnameBase);
+	    goto get_client_port_regcomp_done;
+	}
+
+	// If the regex compliation is successful we will try to extract the interface base name.
+	if ((rc = regexec(regex, req_ifname, nmatch, pmatch, 0)) != 0) {
+	    // If we can't find our regex, means that is using a fixed name.
+	    slprintf(ifnameBase, sizeof(ifnameBase), "%s", ifname);
+	    info("Using static interface naming %s", ifnameBase);
+	    goto get_client_port_regcomp_done;
+	}
+
+	// We need to do a small correction in strlcpy when we are setting the length of the string: +1
+	strlcpy(ifnameBase, req_ifname, pmatch[1].rm_so+1);
+	info("Found dynamic custom interface naming %s", ifnameBase);
+    }
+    else {
+	slprintf(ifnameBase, sizeof(ifnameBase), "%s", PPP_DRV_NAME);
+	info("Using standard format %s", ifnameBase);
+    }
+
+get_client_port_regcomp_done:
+
+    // Build the new pattern using ifnameBase as part for search
+    strlcpy(pattern, ifnameBase, IFNAMSIZ);
+    strcat(pattern, "([0-9]+)");
+
+    /* Compile regular expression */
+    rc = regcomp(regex, pattern, REG_EXTENDED);
+    if (rc != 0) {
+	warn("Warning: couldn't compile the regex \"%s\". Fallback to rc_map2id", pattern);
+	goto get_client_port_regex_done;
+    }
+
+    /* Execute regular expression */
+    // If the regex compliation is successful we will continue to try to extract the interface base name.
+    if ((rc = regexec(regex, ifname, nmatch, pmatch, 0)) != 0) {
+	// If we can't find our regex, means that is using a fixed name.
+	info("ifname %s doesn't match the req_ifname %s. Fallback to rc_map2id", ifname, req_ifname);
+	goto get_client_port_regex_done;
+    }
+    else {
+	slprintf(cport, sizeof(cport), "%.*s", pmatch[1].rm_eo - pmatch[1].rm_so, ifname + pmatch[1].rm_so);
+	port = atoi(cport);
+
 	return port;
     }
+
+get_client_port_regex_done:
     return rc_map2id(ifname);
 }
 

pppd/pppd.8

@@ -1178,10 +1178,12 @@ Sets the ppp unit number (for a ppp0 or ppp1 etc interface name) for outbound
 connections.  If the unit is already in use a dynamically allocated number will
 be used.
 .TP
-.B ifname \fIstring
-Set the ppp interface name for outbound connections.  If the interface name is
-already in use, or if the name cannot be used for any other reason, pppd will
-terminate.
+.B ifname \fIstring%d
+Set the ppp interface name for outbound or inbound connections. If you add
+%d in the end of the string pppd will add ppp unit and will create a new
+interface named like pppoe0, l2tp1, ptpp3. This is valid only for LINUX.
+If is used without %d and the interface name is already in use, or if the 
+name cannot be used for any other reason, pppd will terminate.
 .TP
 .B unset \fIname
 Remove a variable from the environment variable for scripts that are

pppd/sys-linux.c

@@ -83,6 +83,7 @@
 #include <stdlib.h>
 #include <syslog.h>
 #include <string.h>
+#include <regex.h>
 #include <time.h>
 #include <memory.h>
 #include <utmp.h>
@@ -667,6 +668,19 @@ static int make_ppp_unit(void)
 {
 	int x, flags;
 
+	// Variable to create regex
+	regex_t *regex;
+
+	regex = malloc(sizeof(regex_t));
+
+	size_t     nmatch = 2;
+	regmatch_t pmatch[2];
+
+	// We need at least one character in the front of the ifunit
+	char *pattern = ".+(%d)";
+
+	int rc = 0;
+
 	if (ppp_dev_fd >= 0) {
 		dbglog("in make_ppp_unit, already had /dev/ppp open?");
 		close(ppp_dev_fd);
@@ -690,17 +704,62 @@ static int make_ppp_unit(void)
 		error("Couldn't create new ppp unit: %m");
 
 	if (x == 0 && req_ifname[0] != '\0') {
+		/* We can't use ifname as global variable because is not defined yet by set_ifunit function.
+		  This function will be called later in the ppp code.
+		  We have to rewrite almost the same code as in set_ifunit in main.c
+		*/
 		struct ifreq ifr;
-		char t[MAXIFNAMELEN];
+		char old_ifname[MAXIFNAMELEN];
+		char new_ifname[MAXIFNAMELEN];
+		char ifnameBase[IFNAMSIZ];
+
 		memset(&ifr, 0, sizeof(struct ifreq));
-		slprintf(t, sizeof(t), "%s%d", PPP_DRV_NAME, ifunit);
-		strlcpy(ifr.ifr_name, t, IF_NAMESIZE);
-		strlcpy(ifr.ifr_newname, req_ifname, IF_NAMESIZE);
-		x = ioctl(sock_fd, SIOCSIFNAME, &ifr);
-		if (x < 0)
-		    error("Couldn't rename interface %s to %s: %m", t, req_ifname);
-		else
-		    info("Renamed interface %s to %s", t, req_ifname);
+		slprintf(old_ifname, sizeof(old_ifname), "%s%d", PPP_DRV_NAME, ifunit);
+
+		// Compile and create the regex
+		rc = regcomp(regex, pattern, REG_EXTENDED);
+
+		if (rc != 0) {
+		    warn("Warning: couldn't compile the regex \"%s\". Fallback to %s%d format", pattern, PPP_DRV_NAME, ifunit);
+		    slprintf(new_ifname, sizeof(new_ifname), "%s%d", PPP_DRV_NAME, ifunit);
+		    goto set_ifunit_regex_done;
+		} 
+
+		// If the regex compliation is successful we will continue to try to extract the interface base name.
+		if ((rc = regexec(regex, req_ifname, nmatch, pmatch, 0)) != 0) {
+		    // If we can't find our regex, means that we are using a fixed name.
+		    info("Using static interface naming %s format", new_ifname);
+		    slprintf(new_ifname, sizeof(new_ifname), "%s", req_ifname);
+		    goto set_ifunit_regex_done;
+		}
+
+		/* Matching the dynamic name. We need to have no more than IFNAMSIZ - 4 bytes for the base name to have enough room to build ifname + digits.
+		   Linux have a maximum of 16 chars allocated for the interfece names, but only 15 are permited.
+		   So we will have maximum 12 chars for name and 3 chars for digits.
+		*/
+		if (pmatch[1].rm_so >= (IFNAMSIZ-4)) {
+		    warn("Warning: interface base name is too long! Please use up to 12 characters for the name to be able to use at least 3 digits! Fallback to %s%d format", PPP_DRV_NAME, ifunit);
+		    slprintf(new_ifname, sizeof(new_ifname), "%s%d", PPP_DRV_NAME, ifunit);
+		    goto set_ifunit_regex_done;
+		}
+
+		strlcpy(ifnameBase, req_ifname, pmatch[1].rm_so + 1);
+		slprintf(new_ifname, sizeof(new_ifname), "%s%d", ifnameBase, ifunit);
+
+set_ifunit_regex_done:
+		// Free regex
+		regfree(regex);
+
+		if ( strncmp(new_ifname, old_ifname, (strlen(new_ifname) > strlen(new_ifname) ? strlen(new_ifname) : strlen(old_ifname))) ) {
+		    info("Try to rename interface from %s to %s", old_ifname, new_ifname);
+		    strlcpy(ifr.ifr_name, old_ifname, IF_NAMESIZE);
+		    strlcpy(ifr.ifr_newname, new_ifname, IF_NAMESIZE);
+		    x = ioctl(sock_fd, SIOCSIFNAME, &ifr);
+		    if (x < 0)
+			error("Couldn't rename interface %s to %s: %m", old_ifname, new_ifname);
+		    else
+			info("Renamed interface %s to %s", old_ifname, new_ifname);
+		}
 	}
 
 	return x;