[PATCH v3 05/12] net-lwip: add ping command

[Ilias Apalodimas]

[...]

> +static int ping_raw_init(void *recv_arg)
> +{
> +       ping_pcb = raw_new(IP_PROTO_ICMP);
> +       if (!ping_pcb)
> +               return -ENOMEM;
> +
> +       raw_recv(ping_pcb, ping_recv, recv_arg);
> +       raw_bind(ping_pcb, IP_ADDR_ANY);
> +
> +       return 0;
> +}
> +
> +static void ping_raw_stop(void)
> +{
> +       if (ping_pcb != NULL) {

nits, but we usually do if (!ping_pcb) for NULL pointers and variables
that have a value of 0.
Please change it in other files as well


> +               raw_remove(ping_pcb);
> +               ping_pcb = NULL;
> +       }
> +}
> +
> +static void ping_prepare_echo(struct icmp_echo_hdr *iecho)
> +{
> +       ICMPH_TYPE_SET(iecho, ICMP_ECHO);
> +       ICMPH_CODE_SET(iecho, 0);
> +       iecho->chksum = 0;
> +       iecho->id = PING_ID;
> +       iecho->seqno = lwip_htons(++ping_seq_num);
> +
> +       iecho->chksum = inet_chksum(iecho, sizeof(*iecho));
> +}
> +
> +static void ping_send_icmp(struct raw_pcb *raw, const ip_addr_t *addr)
> +{
> +       struct pbuf *p;
> +       struct icmp_echo_hdr *iecho;
> +       size_t ping_size = sizeof(struct icmp_echo_hdr);
> +
> +       p = pbuf_alloc(PBUF_IP, (u16_t)ping_size, PBUF_RAM);
> +       if (!p)
> +               return;
> +
> +       if ((p->len == p->tot_len) && (p->next == NULL)) {

&& !p->next

> +               iecho = (struct icmp_echo_hdr *)p->payload;
> +               ping_prepare_echo(iecho);
> +               raw_sendto(raw, p, addr);
> +       }
> +
> +       pbuf_free(p);
> +}
> +
> +static void ping_send(void *arg)
> +{
> +       struct raw_pcb *pcb = (struct raw_pcb *)arg;
> +
> +       ping_send_icmp(pcb, ping_target);
> +       sys_timeout(PING_DELAY_MS, ping_send, ping_pcb);
> +}
> +
> +static int ping_loop(const ip_addr_t* addr)
> +{
> +       bool alive;
> +       ulong start;
> +       int ret;
> +
> +       printf("Using %s device\n", eth_get_name());
> +
> +       ret = ping_raw_init(&alive);
> +       if (ret < 0)
> +               return ret;
> +       ping_target = addr;
> +       ping_seq_num = 0;
> +
> +       start = get_timer(0);
> +       ping_send(ping_pcb);
> +
> +       do {
> +               eth_rx();
> +               if (alive)
> +                       break;
> +               sys_check_timeouts();
> +               if (ctrlc()) {
> +                       printf("\nAbort\n");
> +                       break;
> +               }
> +       } while (get_timer(start) < PING_TIMEOUT_MS);

I am a bit confused about what happens here.
ping_send() will send the packet, but it will also schedule itself to
rerun after 1 ms and send another ping?

> +
> +       sys_untimeout(ping_send, ping_pcb);

So we need the sys_untimeout() because we queued 2 pings? Because
sys_timeout() is supposed to be an one shot.

Thanks
/Ilias
> +       ping_raw_stop();
> +       ping_target = NULL;
> +
> +       if (alive) {
> +               alive = false;
> +               return 0;
> +       }
> +       printf("ping failed; host %s is not alive\n", ipaddr_ntoa(addr));
> +       return -1;
> +}
> +
> +int do_ping(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
> +{
> +       ip_addr_t addr;
> +
> +       if (argc < 2)
> +               return CMD_RET_USAGE;
> +
> +       if (!ipaddr_aton(argv[1], &addr))
> +               return CMD_RET_USAGE;
> +
> +       if (ping_loop(&addr) < 0)
> +               return CMD_RET_FAILURE;
> +
> +       return CMD_RET_SUCCESS;
> +}
> --
> 2.40.1
>