[Linuxptp-devel] [PATCH V3 5/7] clock: Remember each port's interface index.

[Richard Cochran]

We use a hash table to remember the mapping.  Since our existing hash
table is a simply string hash, we convert the integer index into a decimal
string.  Although hashing integers in this way is sub-optimal, the table
will not be used in a performance critical path.

Signed-off-by: Richard Cochran <richardcoch...@gmail.com>
---
 clock.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/clock.c b/clock.c
index 3b42109..a0124d2 100644
--- a/clock.c
+++ b/clock.c
@@ -31,6 +31,7 @@
 #include "clockcheck.h"
 #include "foreign.h"
 #include "filter.h"
+#include "hash.h"
 #include "missing.h"
 #include "msg.h"
 #include "phc.h"
@@ -38,6 +39,7 @@
 #include "servo.h"
 #include "stats.h"
 #include "print.h"
+#include "sk.h"
 #include "tlv.h"
 #include "tsproc.h"
 #include "uds.h"
@@ -93,6 +95,7 @@ struct clock {
        int pollfd_valid;
        int nports; /* does not include the UDS port */
        int last_port_number;
+       struct hash *index2port;
        int free_running;
        int freq_est_interval;
        int grand_master_capable; /* for 802.1AS only */
@@ -270,6 +273,7 @@ void clock_destroy(struct clock *c)
        }
        port_close(c->uds_port);
        free(c->pollfd);
+       hash_destroy(c->index2port, NULL);
        if (c->clkid != CLOCK_REALTIME) {
                phc_close(c->clkid);
        }
@@ -767,6 +771,8 @@ static int clock_add_port(struct clock *c, int phc_index,
                          struct interface *iface)
 {
        struct port *p, *piter, *lastp = NULL;
+       int fd, index;
+       char key[16];
 
        if (clock_resize_pollfd(c, c->nports + 1)) {
                return -1;
@@ -786,6 +792,23 @@ static int clock_add_port(struct clock *c, int phc_index,
        }
        c->nports++;
        clock_fda_changed(c);
+
+       /* Remember the index to port mapping, for link status tracking. */
+       fd = sk_interface_fd();
+       if (fd < 0) {
+               return -1;
+       }
+       index = sk_interface_index(fd, iface->name);
+       if (index < 0) {
+               return -1;
+       }
+       snprintf(key, sizeof(key), "%d", index);
+       if (hash_insert(c->index2port, key, p)) {
+               pr_err("failed to add port with index %d twice!", index);
+               return -1;
+       }
+       close(fd);
+
        return 0;
 }
 
@@ -1087,6 +1110,11 @@ struct clock *clock_create(enum clock_type type, struct 
config *config,
        }
        clock_fda_changed(c);
 
+       c->index2port = hash_create();
+       if (!c->index2port) {
+               pr_err("failed create index-to-port hash table");
+               return NULL;
+       }
        /* Create the ports. */
        STAILQ_FOREACH(iface, &config->interfaces, list) {
                if (clock_add_port(c, phc_index, timestamping, iface)) {
-- 
2.1.4


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