Printing protocol name based on netinet/in.h

[greenberg]

Hi,

cat /usr/include/netinet/in.h | grep "#define IPPR"
#define IPPROTO_IP              IPPROTO_IP
#define IPPROTO_HOPOPTS         IPPROTO_HOPOPTS
#define IPPROTO_ICMP            IPPROTO_ICMP
#define IPPROTO_IGMP            IPPROTO_IGMP
#define IPPROTO_IPIP            IPPROTO_IPIP
#define IPPROTO_TCP             IPPROTO_TCP
#define IPPROTO_EGP             IPPROTO_EGP
#define IPPROTO_PUP             IPPROTO_PUP
#define IPPROTO_UDP             IPPROTO_UDP
#define IPPROTO_IDP             IPPROTO_IDP
#define IPPROTO_TP              IPPROTO_TP
#define IPPROTO_IPV6            IPPROTO_IPV6
#define IPPROTO_ROUTING         IPPROTO_ROUTING
#define IPPROTO_FRAGMENT        IPPROTO_FRAGMENT
#define IPPROTO_RSVP            IPPROTO_RSVP
#define IPPROTO_GRE             IPPROTO_GRE
#define IPPROTO_ESP             IPPROTO_ESP
#define IPPROTO_AH              IPPROTO_AH
#define IPPROTO_ICMPV6          IPPROTO_ICMPV6
#define IPPROTO_NONE            IPPROTO_NONE
#define IPPROTO_DSTOPTS         IPPROTO_DSTOPTS
#define IPPROTO_MTP             IPPROTO_MTP
#define IPPROTO_ENCAP           IPPROTO_ENCAP
#define IPPROTO_PIM             IPPROTO_PIM
#define IPPROTO_COMP            IPPROTO_COMP
#define IPPROTO_SCTP            IPPROTO_SCTP
#define IPPROTO_RAW             IPPROTO_RAW

I want to be able to print need to print IPPROTO_UDP, IPPROTO_ENCAP, or any other out of structure ip_hdr.

printf("%16d|", ip_hdr->ip_p);
						/*
						switch (ip_hdr->ip_p) {
                        case IPPROTO_TCP:
                                printf("%8s|", "TCP");
                                break;
                        case IPPROTO_UDP:
                                printf("%8s|", "UDP");
                                break;
                        case IPPROTO_ICMP:
                                printf("%8s|", "ICMP");
                                break;
                        case IPPROTO_IP:
                                printf("%8s|", "IP");
                                break;
                        default:
                                printf("%8s|", "UNKNOWN");
                                return;
                        }
						*/

Currently, I just match with the CASE. Who knows another way?


Thank you in advance!

[cas]

As far as I'm aware, there is no function that does what you want. Your approach is really all you can do.

I would recommend using a script to generate such a function, though. It should make life easier if you need to add types in the future:

#!/bin/sh
protos="IP ICMP" # list them all
echo "const char *proto_name(int proto) {"
echo "  switch(proto) {"
for proto in ${protos}
do
  cat <<EOF
#ifdef IPPROTO_${proto}
    case IPPROTO_${proto}: return "${proto}";
#endif
EOF
done
cat <<EOF
  }
  return "UNKNOWN";
}
EOF

To be portable, you want to check for the existence of each macro (a few you have listed are standard, but many are not).

[anduril462]

Are you looking for something like this: getservbyport(3): service entry - Linux man page

[CommonTater]

Hi,
I want to be able to print need to print IPPROTO_UDP, IPPROTO_ENCAP, or any other out of structure ip_hdr.

Currently, I just match with the CASE. Who knows another way?
Thank you in advance!

Each protocal is assigned a number... You could build a .h file with an constant array of strings... the array index is the protocal number, the string is the protocal name.... Then you can printf("%s" IPPROTO_UDP); to display it's name.

[Salem]

Perhaps

$ cat foo.c
#include <stdio.h>

#define MKSTR(x)    #x
#define FOO 10

int main ( ) {
  printf("%s=%d\n", MKSTR(FOO), FOO );
  return 0;
}

$ gcc foo.c
$ ./a.out 
FOO=10