brctl: add support for showmacs command

function                                             old     new   delta
brctl_main                                           680     974    +294
packed_usage                                       33167   33187     +20
compare_fdbs                                           -      19     +19
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/0 up/down: 333/0)             Total: 333 bytes

Signed-off-by: Martin Lewis <martin.lewis.x84@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 92 insertions, 19 deletions

diff --git a/networking/brctl.c b/networking/brctl.c
index 586ca9b0c..ba5b6226f 100644
--- a/networking/brctl.c
+++ b/networking/brctl.c
@@ -61,10 +61,10 @@
 //usage:     "\n        setbridgeprio BRIDGE PRIO       Set bridge priority"
 //usage:     "\n        setportprio BRIDGE IFACE PRIO   Set port priority"
 //usage:     "\n        setpathcost BRIDGE IFACE COST   Set path cost"
+//usage:     "\n        showmacs BRIDGE                 List MAC addresses"
 //usage:        )
 // Not yet implemented:
 //                      hairpin BRIDGE IFACE on|off     Hairpin on/off
-//                      showmacs BRIDGE                 List mac addrs
 //                      showstp BRIDGE                  Show stp info
 
 #include "libbb.h"
@@ -196,6 +196,89 @@ static void write_uint(const char *name, const char *leaf, unsigned val)
                 bb_simple_perror_msg_and_die(name);
         close(fd);
 }
+
+struct fdb_entry {
+        uint8_t mac_addr[6];
+        uint8_t port_no;
+        uint8_t is_local;
+        uint32_t ageing_timer_value;
+        uint8_t port_hi;
+        uint8_t pad0;
+        uint16_t unused;
+};
+
+static int compare_fdbs(const void *_f0, const void *_f1)
+{
+        const struct fdb_entry *f0 = _f0;
+        const struct fdb_entry *f1 = _f1;
+
+        return memcmp(f0->mac_addr, f1->mac_addr, 6);
+}
+
+static size_t read_bridge_forward_db(const char *name, struct fdb_entry **_fdb)
+{
+        struct fdb_entry *fdb;
+        size_t nentries;
+        char *path;
+        int fd;
+        ssize_t cc;
+
+        path = concat_path_file(name, "brforward");
+        fd = open(path, O_RDONLY);
+        free(path);
+        if (fd < 0)
+                bb_error_msg_and_die("bridge %s does not exist", name);
+
+        fdb = NULL;
+        nentries = 0;
+        for (;;) {
+                fdb = xrealloc_vector(fdb, 4, nentries);
+                cc = full_read(fd, &fdb[nentries], sizeof(*fdb));
+                if (cc == 0) {
+                        break;
+                }
+                if (cc != sizeof(*fdb)) {
+                        bb_perror_msg_and_die("can't read bridge %s forward db", name);
+                }
+                ++nentries;
+        }
+
+        close(fd);
+
+        qsort(fdb, nentries, sizeof(*fdb), compare_fdbs);
+
+        *_fdb = fdb;
+        return nentries;
+}
+
+static void show_bridge_macs(const char *name)
+{
+        struct fdb_entry *fdb;
+        size_t nentries;
+        size_t i;
+
+        nentries = read_bridge_forward_db(name, &fdb);
+
+        printf("port no\tmac addr\t\tis local?\tageing timer\n");
+        for (i = 0; i < nentries; ++i) {
+                const struct fdb_entry *f = &fdb[i];
+                unsigned long tvmsec = 10UL * f->ageing_timer_value;
+                unsigned tv_sec = tvmsec / 1000;
+                unsigned tv_msec = tvmsec % 1000;
+                printf("%3u\t"
+                        "%.2x:%.2x:%.2x:%.2x:%.2x:%.2x\t"
+                        "%s\t\t"
+                        "%4u.%.2u\n",
+                        f->port_no,
+                        f->mac_addr[0], f->mac_addr[1], f->mac_addr[2],
+                        f->mac_addr[3], f->mac_addr[4], f->mac_addr[5],
+                        (f->is_local ? "yes" : "no"),
+                        tv_sec, tv_msec / 10
+                );
+        }
+
+        free(fdb);
+}
 #endif
 
 int brctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -208,6 +291,7 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
                 "setageing\0" "setfd\0" "sethello\0" "setmaxage\0"
                 "setpathcost\0" "setportprio\0"
                 "setbridgeprio\0"
+                "showmacs\0"
         )
         IF_FEATURE_BRCTL_SHOW("show\0");
         enum { ARG_addbr = 0, ARG_delbr, ARG_addif, ARG_delif
@@ -215,7 +299,8 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
                         ARG_stp,
                         ARG_setageing, ARG_setfd, ARG_sethello, ARG_setmaxage,
                         ARG_setpathcost, ARG_setportprio,
-                        ARG_setbridgeprio
+                        ARG_setbridgeprio,
+                        ARG_showmacs
                 )
                 IF_FEATURE_BRCTL_SHOW(, ARG_show)
         };
@@ -299,6 +384,11 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
                         return EXIT_SUCCESS;
                 }
 
+                if (key == ARG_showmacs) {
+                        show_bridge_macs(br);
+                        return EXIT_SUCCESS;
+                }
+
                 if (!*argv) /* all but 'addbr/delbr' need at least two arguments */
                         bb_show_usage();
 
@@ -365,23 +455,6 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
                         //goto done_next_argv;
                         return EXIT_SUCCESS;
                 }
-
-/* TODO: "showmacs BR"
- *      port no\tmac addr\t\tis local?\tageing timer
- *      <sp><sp>1\txx:xx:xx:xx:xx:xx\tno\t\t<sp><sp><sp>1.31
- *      port no mac addr                is local?       ageing timer
- *        1     xx:xx:xx:xx:xx:xx       no                 1.31
- * Read fixed-sized records from /sys/class/net/BR/brforward:
- *      struct __fdb_entry {
- *              uint8_t  mac_addr[ETH_ALEN];
- *              uint8_t  port_no; //lsb
- *              uint8_t  is_local;
- *              uint32_t ageing_timer_value;
- *              uint8_t  port_hi;
- *              uint8_t  pad0;
- *              uint16_t unused;
- *      };
- */
 #endif
                 /* always true: if (key == ARG_addif || key == ARG_delif) */ {
                         /* addif or delif */