+ return oldrxbytes ? fmt_scaled((rxbytes - oldrxbytes) /
+ interval * 1000) : NULL;
+ }
+
+ const char *
+ netspeed_tx(const char *interface)
+ {
+ struct ifaddrs *ifal, *ifa;
+ struct if_data *ifd;
+ uint64_t oldtxbytes;
+ static uint64_t txbytes = 0;
+ extern const unsigned int interval;
+ int if_ok = 0;
+
+ oldtxbytes = txbytes;
+
+ if (getifaddrs(&ifal) == -1) {
+ warn("getifaddrs failed");
+ return NULL;
+ }
+ txbytes = 0;
+ for (ifa = ifal; ifa; ifa = ifa->ifa_next) {
+ if (!strcmp(ifa->ifa_name, interface) &&
+ (ifd = (struct if_data *)ifa->ifa_data)) {
+ txbytes += ifd->ifi_obytes, if_ok = 1;
+ }
+ }
+ freeifaddrs(ifal);
+ if (!if_ok) {
+ warn("reading 'if_data' failed");
+ return NULL;
+ }
+
+ return oldtxbytes ? fmt_scaled((txbytes - oldtxbytes) /
+ interval * 1000) : NULL;