Merge remote-tracking branch 'remotes/theo/tobast/v6tethered-reimplem' into v4viav6

CREDITS

@@ -22,6 +22,7 @@ This file lists people who have contributed to babeld (in alphabetical order):
     Matthieu Boutier              <boutier at irif dot fr>
     Sawssen Hadded                <saw dot hadded at gmail dot com>
     Stephane Glondu               <steph at glondu dot net>
+    Théophile Bastian             <theophile dot bastian at ens dot fr>
     Thomas Petazzoni              <thomas dot petazzoni at free-electrons dot com>
     Toke Høiland-Jørgensen        <toke at toke dot dk>
     Vincent Gross                 <dermiste at screwball-coders dot net>

babeld.c

@@ -63,6 +63,7 @@ int debug = 0;
 int link_detect = 0;
 int all_wireless = 0;
 int has_ipv6_subtrees = 0;
+int has_v4ov6 = 0;
 int default_wireless_hello_interval = -1;
 int default_wired_hello_interval = -1;
 int resend_delay = -1;
@@ -151,6 +152,7 @@ main(int argc, char **argv)
     protocol_port = 6696;
     change_smoothing_half_life(4);
     has_ipv6_subtrees = kernel_has_ipv6_subtrees();
+    has_v4ov6 = kernel_has_v4ov6();
 
     while(1) {
         opt = getopt(argc, argv,

babeld.h

@@ -92,6 +92,7 @@ extern const char *logfile, *pidfile, *state_file;
 extern int link_detect;
 extern int all_wireless;
 extern int has_ipv6_subtrees;
+extern int has_v4ov6;
 
 extern unsigned char myid[8];
 extern int have_id;

babeld.man

@@ -200,6 +200,11 @@ This specifies whether to use native source-specific IPv6 forwarding
 rather than multiple routing tables.  The default is chosen automatically
 depending on the kernel version.
 .TP
+.BR v4-over-v6 " {" true | false }
+This specifies whether to use v4-over-v6 routes (IPv4 routes with an IPv6
+next-hop).  This should not be enabled unless your kernel supports it.  The
+default is chosen automatically depending on the kernel version.
+.TP
 .BI debug " level"
 This specifies the debugging level, and is equivalent to the command-line
 option

configuration.c

@@ -1029,6 +1029,7 @@ parse_option(int c, gnc_t gnc, void *closure, char *token)
               strcmp(token, "daemonise") == 0 ||
               strcmp(token, "skip-kernel-setup") == 0 ||
               strcmp(token, "ipv6-subtrees") == 0 ||
+              strcmp(token, "v4-over-v6") == 0 ||
               strcmp(token, "reflect-kernel-metric") == 0) {
         int b;
         c = getbool(c, &b, gnc, closure);
@@ -1045,6 +1046,8 @@ parse_option(int c, gnc_t gnc, void *closure, char *token)
             skip_kernel_setup = b;
         else if(strcmp(token, "ipv6-subtrees") == 0)
             has_ipv6_subtrees = b;
+        else if(strcmp(token, "v4-over-v6") == 0)
+            has_v4ov6 = b;
         else if(strcmp(token, "reflect-kernel-metric") == 0)
             reflect_kernel_metric = b;
         else

kernel.h

@@ -95,3 +95,10 @@ int gettime(struct timeval *tv);
 int read_random_bytes(void *buf, int len);
 int kernel_older_than(const char *sysname, int version, int sub_version);
 int kernel_has_ipv6_subtrees(void);
+int kernel_has_v4ov6(void);
+int add_rule(int prio, const unsigned char *src_prefix, int src_plen,
+             int table);
+int flush_rule(int prio, int family);
+int change_rule(int new_prio, int old_prio, const unsigned char *src, int plen,
+                int table);
+

kernel_netlink.c

@@ -943,6 +943,14 @@ kernel_has_ipv6_subtrees(void)
     return (kernel_older_than("Linux", 3, 11) == 0);
 }
 
+int
+kernel_has_v4ov6(void)
+{
+    /* v4-over-v6 was introduced in Linux by commit
+       d15662682db232da77136cd348f4c9df312ca6f9 first released as 5.2 */
+    return (kernel_older_than("Linux", 5, 2) == 0);
+}
+
 int
 kernel_route(int operation, int table,
              const unsigned char *dest, unsigned short plen,
@@ -956,7 +964,7 @@ kernel_route(int operation, int table,
     struct rtmsg *rtm;
     struct rtattr *rta;
     int len = sizeof(buf.raw);
-    int rc, ipv4, use_src = 0;
+    int rc, ipv4, is_v4_over_v6, use_src = 0;
 
     if(!nl_setup) {
         fprintf(stderr,"kernel_route: netlink not initialized.\n");
@@ -978,8 +986,7 @@ kernel_route(int operation, int table,
 
     /* Check that the protocol family is consistent. */
     if(plen >= 96 && v4mapped(dest)) {
-        if(!v4mapped(gate) ||
-           !v4mapped(src)) {
+        if(!v4mapped(src)) {
             errno = EINVAL;
             return -1;
         }
@@ -1018,7 +1025,8 @@ kernel_route(int operation, int table,
     }
 
 
-    ipv4 = v4mapped(gate);
+    ipv4 = v4mapped(dest);
+    is_v4_over_v6 = ipv4 && !v4mapped(gate);
     use_src = !is_default(src, src_plen);
     if(use_src) {
         if(ipv4 || !has_ipv6_subtrees) {
@@ -1095,22 +1103,31 @@ kernel_route(int operation, int table,
         *(int*)RTA_DATA(rta) = ifindex;
 
 #define ADD_IPARG(type, addr) \
-        do if(ipv4) {                                                   \
+        do { \
             rta = RTA_NEXT(rta, len); \
-            rta->rta_len = RTA_LENGTH(sizeof(struct in_addr));          \
             rta->rta_type = type; \
+            if(v4mapped(addr)) { \
+                rta->rta_len = RTA_LENGTH(sizeof(struct in_addr)); \
                 memcpy(RTA_DATA(rta), addr + 12, sizeof(struct in_addr)); \
             } else { \
-            rta = RTA_NEXT(rta, len);                                   \
+                if(type == RTA_VIA) { \
+                    rta->rta_len = RTA_LENGTH(sizeof(struct in6_addr) + 2); \
+                    *((sa_family_t*) RTA_DATA(rta)) = AF_INET6; \
+                    memcpy(RTA_DATA(rta) + 2, addr, sizeof(struct in6_addr)); \
+                } else { \
                     rta->rta_len = RTA_LENGTH(sizeof(struct in6_addr)); \
-            rta->rta_type = type;                                       \
                     memcpy(RTA_DATA(rta), addr, sizeof(struct in6_addr)); \
+                } \
+            } \
         } while (0)
 
+        if(is_v4_over_v6)
+            ADD_IPARG(RTA_VIA, gate);
+        else
             ADD_IPARG(RTA_GATEWAY, gate);
+
         if(pref_src)
             ADD_IPARG(RTA_PREFSRC, pref_src);
-
 #undef ADD_IPARG
     } else {
         *(int*)RTA_DATA(rta) = -1;

kernel_socket.c

@@ -395,6 +395,12 @@ kernel_has_ipv6_subtrees(void)
     return 0;
 }
 
+int
+kernel_has_v4ov6(void)
+{
+    return 0;
+}
+
 int
 kernel_route(int operation, int table,
              const unsigned char *dest, unsigned short plen,

message.h

@@ -47,6 +47,13 @@ THE SOFTWARE.
 #define SUBTLV_TIMESTAMP 3       /* Used to compute RTT. */
 #define SUBTLV_SOURCE_PREFIX 128 /* Source-specific routing. */
 
+/* Address encodings */
+#define AE_WILDCARD 0
+#define AE_IPV4 1
+#define AE_IPV6 2
+#define AE_IPV6_LOCAL 3
+#define AE_V4OV6 4
+
 extern unsigned short myseqno;
 extern struct timeval seqno_time;
 

util.c

@@ -502,6 +502,12 @@ v4tov6(unsigned char *dst, const unsigned char *src)
     memcpy(dst + 12, src, 4);
 }
 
+int
+ae_is_v4(int ae)
+{
+    return ae == 1 || ae == 4;
+}
+
 int
 daemonise()
 {

util.h

@@ -100,6 +100,7 @@ int wait_for_fd(int direction, int fd, int msecs);
 int martian_prefix(const unsigned char *prefix, int plen) ATTRIBUTE ((pure));
 int linklocal(const unsigned char *address) ATTRIBUTE ((pure));
 int v4mapped(const unsigned char *address) ATTRIBUTE ((pure));
+int ae_is_v4(int ae) ATTRIBUTE ((pure));
 void v4tov6(unsigned char *dst, const unsigned char *src);
 int daemonise(void);
 int set_src_prefix(unsigned char *src_addr, unsigned char *src_plen);