Re: [PATCH 1/1] tidbits: net-udp: solicit new client for server mode

[Philippe Gerum <rpm@xenomai.org>]

Hannes Diethelm <hannes.diethelm@gmail.com> writes:

> This fixes random EINPROGRESS at init or during runtime.
>
> Also correct whitespaces and make stdout more consistent.
>
> Signed-off-by: Hannes Diethelm <hannes.diethelm@gmail.com>
> ---
>  tidbits/oob-net-udp.c | 58 +++++++++++++++++++++++++++++++++++++------
>  1 file changed, 50 insertions(+), 8 deletions(-)
>
> diff --git a/tidbits/oob-net-udp.c b/tidbits/oob-net-udp.c
> index 11b8459..7af834f 100644
> --- a/tidbits/oob-net-udp.c
> +++ b/tidbits/oob-net-udp.c
> @@ -50,12 +50,12 @@ static void usage(void)
>  }
>  
>  static void print_addr(char* text, struct sockaddr_in *addr){
> -    char ip_str[INET_ADDRSTRLEN+1];
> -    inet_ntop(AF_INET, &(addr->sin_addr), ip_str, sizeof(ip_str));
> -    evl_printf("%s--------\n", text);
> -    evl_printf("IP-Address: %s\n", ip_str);
> -    evl_printf("Port:       %d\n", ntohs(addr->sin_port));
> -    evl_printf("Family:     %d\n", addr->sin_family);
> +	char ip_str[INET_ADDRSTRLEN+1];
> +	inet_ntop(AF_INET, &(addr->sin_addr), ip_str, sizeof(ip_str));
> +	evl_printf("== %s\n", text);
> +	evl_printf("   ip-address: %s\n", ip_str);
> +	evl_printf("   port:       %d\n", ntohs(addr->sin_port));
> +	evl_printf("   family:     %d\n", addr->sin_family);
>  }
>  
>  static void sender(int s, const char *text, int mcount,
> @@ -226,6 +226,8 @@ static void client(int s, const char *text, int mcount,
>  	free(tbuf);
>  }
>  
> +#define SERVER_ADDR_LIST_SIZE 64
> +
>  static void server(int s, const char *text, int mcount,
>  		struct sockaddr_in *addr, int iter)
>  {
> @@ -236,6 +238,9 @@ static void server(int s, const char *text, int mcount,
>  	ssize_t ret;
>  	char *tbuf;
>  	char rbuf[16384];
> +	in_addr_t addr_list[SERVER_ADDR_LIST_SIZE]={};
                                                  ^ missing whitespaces
> +	size_t addr_list_fill=0;
> +	bool solicit_done;
>  
>  	tlen = (strlen(text) + 1) * mcount;
>  	tbuf = malloc(tlen);
> @@ -276,6 +281,39 @@ static void server(int s, const char *text, int mcount,
>  			evl_printf(" (TRUNCATED)");
>  		evl_printf(": %.*s\n", (int)ret, rbuf);
>  
> +		/*
> +		 * We need to call evl_net_solicit for each new
> +		 * client once before sending data. This will break
> +		 * realtime for the first response.
> +		 * If this is not done and the ARP address is not
> +		 * yet in cache or garbage-collected, oob_sendmsg
> +		 * will return EINPROGRESS on start or during runtime.
> +		 */

We can happily send redundant solicit requests to the core, no need to
filter out cached addresses, evl_net_solicit() will do the right thing.

> +		solicit_done = false;
> +		for(size_t i = 0; i < addr_list_fill && !solicit_done; i++){

                   ^ missing whitespace

> +			if(addr_list[i] == _addr.sin_addr.s_addr){
                          ^ missing whitespace

> +				solicit_done = true;
> +			}
> +		}
> +		if(!solicit_done){
> +			if(verbosity){
> +				char ip_str[INET_ADDRSTRLEN+1];
> +				inet_ntop(AF_INET, &(_addr.sin_addr), ip_str, sizeof(ip_str));
> +				evl_printf("== client %s first seen: evl_net_solicit\n", ip_str);
> +			}
> +			ret = evl_net_solicit(s, (const struct sockaddr *)&_addr,
> +					EVL_NEIGH_PERMANENT);
> +			if (ret)
> +				error(1, -ret, "evl_net_solicit()");
> +
> +			if(addr_list_fill < SERVER_ADDR_LIST_SIZE){
> +				addr_list[addr_list_fill] = _addr.sin_addr.s_addr;
> +				addr_list_fill ++;
                                              ^ extraneous whitespace

> +			}else{
> +				error(1, EPERM, "address list full");
> +			}
> +		}
> +
>  		iov.iov_base = tbuf;
>  		iov.iov_len = tlen;
>  		msghdr.msg_iov = &iov;
> @@ -433,7 +471,7 @@ int main(int argc, char *argv[])
>  		receiver(s, &addr, iter);
>  	} else if (mode == CLIENT) {
>  		if (verbosity)
> -			printf("== client mode (<= %s:%d)\n", ip, port);
> +			printf("== client mode (<=> %s:%d)\n", ip, port);
>  
>  		/*
>  		 * Guarantee a mere oob path from the first packet
> @@ -449,8 +487,12 @@ int main(int argc, char *argv[])
>  		client(s, text, mcount, &addr, iter, delay);
>  	} else if (mode == SERVER) {
>  		if (verbosity)
> -			printf("== server mode (<= %s:%d)\n", ip, port);
> +			printf("== server mode (<=> %s:%d)\n", ip, port);
>  
> +		/*
> +		 * The server calls evl_net_solicit() internally
> +		 * for each new ip address.
> +		 */
>  		server(s, text, mcount, &addr, iter);
>  	} else {
>  		error(1, 0, "Mode not implemented");

-- 
Philippe.