[SLOF] [PATCH v3 2/3] ping: add netmask in the ping argument

Nikunj A Dadhania nikunj at linux.vnet.ibm.com
Tue May 3 17:59:05 AEST 2016


Thomas Huth <thuth at redhat.com> writes:

> On 03.05.2016 06:01, Nikunj A Dadhania wrote:
>> The current ping command does not take netmask as argument, updated the
>> ping command to take "client-ip/nn" format ip address.
>> 
>> Add routine to return netmask(class based), when not provided by user.
>> 
>> Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
>> ---
>>  clients/net-snk/app/netapps/args.c | 44 ++++++++++++++++++++++++++++++++++----
>>  clients/net-snk/app/netapps/args.h |  1 +
>>  clients/net-snk/app/netapps/ping.c | 21 ++++++++++++++++--
>>  clients/net-snk/app/netlib/ipv4.c  | 21 ++++++++++++++++++
>>  clients/net-snk/app/netlib/ipv4.h  |  1 +
>>  slof/fs/loaders.fs                 |  4 ++--
>>  6 files changed, 84 insertions(+), 8 deletions(-)
>> 
>> diff --git a/clients/net-snk/app/netapps/args.c b/clients/net-snk/app/netapps/args.c
>> index 52215e6..ed25c7c 100644
>> --- a/clients/net-snk/app/netapps/args.c
>> +++ b/clients/net-snk/app/netapps/args.c
>> @@ -98,20 +98,22 @@ argncpy(const char *arg_str, unsigned int index, char *buffer,
>>  }
>>  
>>  /**
>> - * Converts "255.255.255.255" -> char[4] = { 0xff, 0xff, 0xff, 0xff }
>> + * Converts "255.255.255.255/nn" -> char[4] = { 0xff, 0xff, 0xff, 0xff }
>> + *                                  *netmask = subnet_netmask(nn)
>>   *
>>   * @param  str        string to be converted
>>   * @param  ip         in case of SUCCESS - 32-bit long IP
>> -                      in case of FAULT - zero
>> + *                    in case of FAULT - zero
>> + * @param  netmask    return netmask if there is a valid /nn encoding in IP
>>   * @return            TRUE - IP converted successfully;
>>   *                    FALSE - error condition occurs (e.g. bad format)
>>   */
>>  int
>> -strtoip(const char *str, char ip[4])
>> +strtoip_netmask(const char *str, char ip[4], unsigned int *netmask)
>>  {
>>  	char octet[10];
>>  	int res;
>> -	unsigned int i = 0, len;
>> +	unsigned int i = 0, len, has_nn = 0;
>>  
>>  	while (*str != 0) {
>>  		if (i > 3 || !isdigit(*str))
>> @@ -123,6 +125,14 @@ strtoip(const char *str, char ip[4])
>>  			strncpy(octet, str, len);
>>  			octet[len] = 0;
>>  			str += len;
>> +		} else if (strstr(str, "\\") != NULL) {
>> +			len = (short) (strstr(str, "\\") - str);
>
> Shouldn't that be a forward slash instead? Or will this cause trouble
> with the slash handling from the Forth code? (in the latter case, you
> should at least adapt the 'Converts "255.255.255.255/nn"' comment in
> front of this function, I think)

Yes, forward slash has problem with parsing, even the file handling for
tftpboot uses backward slash. I will update the comment accordingly.

>
> Anyway, you could also use strchr() instead of strstr() as a small
> optimization, I think.
>
>> +			if (len >= 10)
>> +				return 0;
>> +			strncpy(octet, str, len);
>> +			octet[len] = 0;
>> +			str += len;
>> +			has_nn = 1;
>>  		} else {
>>  			strncpy(octet, str, 9);
>>  			octet[9] = 0;
>> @@ -135,9 +145,35 @@ strtoip(const char *str, char ip[4])
>>  		i++;
>>  		if (*str == '.')
>>  			str++;
>> +		if(has_nn) {
>> +			str++;
>> +			strncpy(octet, str, 9);
>> +			octet[9] = 0;
>> +			res = strtol(octet, NULL, 10);
>> +			str += strlen(octet);
>> +			if (res > 31 || res < 1)
>> +				return 0;
>> +			if (netmask)
>> +				*netmask = (0xFFFFFFFFUL << (32 - res)) & 0xFFFFFFFFUL;
>
> I think you could simply do without the final "& 0xFFFFFFFFUL" here.

Being more careful :-)

> And for the first 0xFFFFFFFF, you also don't need the UL suffix, do
> you?

Should be fine.

>
>> +		}
>>  	}
>>  
>>  	if (i != 4)
>>  		return 0;
>>  	return -1;
>>  }
>> +
>> +/**
>> + * Converts "255.255.255.255" -> char[4] = { 0xff, 0xff, 0xff, 0xff }
>> + *
>> + * @param  str        string to be converted
>> + * @param  ip         in case of SUCCESS - 32-bit long IP
>> + in case of FAULT - zero
>> + * @return            TRUE - IP converted successfully;
>> + *                    FALSE - error condition occurs (e.g. bad format)
>> + */
>> +int
>> +strtoip(const char *str, char ip[4])
>> +{
>> +	return strtoip_netmask(str, ip, NULL);
>> +}
>> diff --git a/clients/net-snk/app/netapps/args.h b/clients/net-snk/app/netapps/args.h
>> index b80982a..1ede9a8 100644
>> --- a/clients/net-snk/app/netapps/args.h
>> +++ b/clients/net-snk/app/netapps/args.h
>> @@ -18,5 +18,6 @@ unsigned int get_args_count(const char *);
>>  unsigned int get_arg_length(const char *);
>>  char *argncpy(const char *, unsigned int, char *, unsigned int);
>>  int strtoip(const char *, char[4]);
>> +int strtoip_netmask(const char *, char[4], unsigned int *netmask);
>>  
>>  #endif				/* _ARGS_H */
>> diff --git a/clients/net-snk/app/netapps/ping.c b/clients/net-snk/app/netapps/ping.c
>> index 4facf06..bd8f2d3 100644
>> --- a/clients/net-snk/app/netapps/ping.c
>> +++ b/clients/net-snk/app/netapps/ping.c
>> @@ -35,13 +35,15 @@ struct ping_args {
>>  		unsigned int integer;
>>  	} gateway_ip;
>>  	unsigned int timeout;
>> +	/* Netmask 192.168.1.10/24 format */
>
> What do you mean with "192.168.1.10/24 format" here? You store here the
> real netmask, not the prefix length, right?

You are right, my earlier code was storing just th /nn part, which i had
later changed to netmask, will update the comment.

>
>> +	unsigned int netmask;
>>  };
>>  
>>  static void
>>  usage(void)
>>  {
>>  	printf
>> -	    ("\nping device-path:[device-args,]server-ip,[client-ip],[gateway-ip][,timeout]\n");
>> +	    ("\nping device-path:[device-args,]server-ip,[client-ip[\\nn]],[gateway-ip][,timeout]\n");
>>  }
>>  
>> @@ -82,7 +84,7 @@ parse_args(const char *args, struct ping_args *ping_args)
>>  	}
>>  
>>  	argncpy(args, 0, buf, 64);
>> -	if (!strtoip(buf, ping_args->client_ip.string)) {
>> +	if (!strtoip_netmask(buf, ping_args->client_ip.string, &ping_args->netmask)) {
>>  		/* this should have been the client (our) IP address */
>>  		return -1;
>>  	} else {
>> @@ -112,6 +114,7 @@ ping(int argc, char *argv[])
>>  	int fd_device;
>>  	struct ping_args ping_args;
>>  	uint8_t own_mac[6];
>> +	uint32_t netmask;
>>  
>>  	memset(&ping_args, 0, sizeof(struct ping_args));
>>  
>> @@ -163,6 +166,14 @@ ping(int argc, char *argv[])
>>  
>>  	} else {
>>  		memcpy(&fn_ip.own_ip, &ping_args.client_ip.integer, 4);
>> +		if (!ping_args.netmask) {
>> +			/* Netmask is not provided, assume default according to
>> +			 * the network class
>> +			 */
>> +			ping_args.netmask = get_default_ipv4_netmask(ping_args.client_ip.string);
>> +		}
>> +		set_ipv4_netmask(ping_args.netmask);
>> +
>>  		arp_failed = 1;
>>  		printf("  Own IP address: ");
>>  	}
>> @@ -174,6 +185,12 @@ ping(int argc, char *argv[])
>>  	       ((fn_ip.own_ip >> 24) & 0xFF), ((fn_ip.own_ip >> 16) & 0xFF),
>>  	       ((fn_ip.own_ip >> 8) & 0xFF), (fn_ip.own_ip & 0xFF));
>>  
>> +	if ((netmask = get_ipv4_netmask())) {
>
> Just a matter of taste - but could you maybe write that in two lines:
>
> 	netmask = get_ipv4_netmask();
> 	if (netmask) ...
>
>> +		printf("  Netmask : ");
>> +		printf("%d.%d.%d.%d\n", ((netmask >> 24) & 0xFF), ((netmask >> 16) & 0xFF),
>> +		       ((netmask >> 8) & 0xFF), (netmask & 0xFF));
>> +	}
>> +
>>  	memcpy(&fn_ip.server_ip, &ping_args.server_ip.integer, 4);
>>  	printf("  Ping to %d.%d.%d.%d ", ((fn_ip.server_ip >> 24) & 0xFF),
>>  	       ((fn_ip.server_ip >> 16) & 0xFF),
>> diff --git a/clients/net-snk/app/netlib/ipv4.c b/clients/net-snk/app/netlib/ipv4.c
>> index 2b92c77..3a1a789 100644
>> --- a/clients/net-snk/app/netlib/ipv4.c
>> +++ b/clients/net-snk/app/netlib/ipv4.c
>> @@ -250,6 +250,27 @@ uint32_t get_ipv4_netmask(void)
>>  }
>>  
>>  /**
>> + * IPv4: Get the default subnet mask according to the IP class
>> + *
>> + * @param ip_addr IPv4 address
>> + * @return default netmask according to the IP class
>> + */
>> +uint32_t get_default_ipv4_netmask(char *ip_addr)
>> +{
>> +	unsigned char top;
>> +
>> +	top = ip_addr[0];
>> +	if (top > 0 && top < 128)
>> +		return 0xFF000000; /* Class A: 255.0.0.0 */
>> +	else if (top >= 128 && top < 192)
>> +		return 0xFFFF0000; /* Class B: 255.255.0.0 */
>> +	else if (top >= 192 && top < 224)
>> +		return 0xFFFFFF00; /* Class C: 255.255.255.0 */
>> +	else
>> +		return 0;
>> +}
>> +
>> +/**
>>   * IPv4: Creates IP-packet. Places IP-header in a packet and fills it
>>   *       with corresponding information.
>>   *       <p>
>> diff --git a/clients/net-snk/app/netlib/ipv4.h b/clients/net-snk/app/netlib/ipv4.h
>> index 18821ea..5717c9a 100644
>> --- a/clients/net-snk/app/netlib/ipv4.h
>> +++ b/clients/net-snk/app/netlib/ipv4.h
>> @@ -69,6 +69,7 @@ extern void     set_ipv4_router(uint32_t router_ip);
>>  extern uint32_t get_ipv4_router(void);
>>  extern void     set_ipv4_netmask(uint32_t subnet_mask);
>>  extern uint32_t get_ipv4_netmask(void);
>> +extern uint32_t get_default_ipv4_netmask(char *ip_addr);
>>  
>>  extern int   (*send_ip) (int fd, void *, int);
>>  
>> diff --git a/slof/fs/loaders.fs b/slof/fs/loaders.fs
>> index 1478c70..8ae502d 100644
>> --- a/slof/fs/loaders.fs
>> +++ b/slof/fs/loaders.fs
>> @@ -70,7 +70,7 @@ CREATE load-list 2 cells allot load-list 2 cells erase
>>     THEN
>>  ;
>>  
>> -: ping  ( "{device-path:[device-args,]server-ip,[client-ip],[gateway-ip][,timeout]}" -- )
>> +: ping  ( "{device-path:[device-args,]server-ip,[client-ip[\nn]],[gateway-ip][,timeout]}" -- )
>>     my-self >r current-node @ >r  \ Save my-self
>>     (parse-line) open-dev dup  IF
>>        dup to my-self dup ihandle>phandle set-node
>> @@ -83,7 +83,7 @@ CREATE load-list 2 cells allot load-list 2 cells erase
>>        swap close-dev
>>     ELSE
>>        cr
>> -      ." Usage: ping device-path:[device-args,]server-ip,[client-ip],[gateway-ip][,timeout]"
>> +      ." Usage: ping device-path:[device-args,]server-ip,[client-ip[\nn]],[gateway-ip][,timeout]"
>>        cr drop
>>     THEN
>>     r> set-node r> to my-self  \ Restore my-self
>> 
>
> Apart from the nits, the patch looks fine to me.

Will send a patch with updates

>
>  Thomas

Regards
Nikunj



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