buf = blobmsg_alloc_string_buffer(&b, "source", buflen);
inet_ntop(af, &route->source, buf, buflen);
- snprintf(buf + strlen(buf), 4, "/%u", route->sourcemask);
+ snprintf(buf + strlen(buf), buflen - strlen(buf), "/%u", route->sourcemask);
blobmsg_add_string_buffer(&b);
blobmsg_close_table(&b, r);