Networking/Ideas/NetworkNameResolution

🔗 Some ideas for name resolution in linux distributions

🔗 Resolve a host name to a list of network layer addresses

🔗 Use cases

IP-based access lists
Network layer testing tools
Any tools working with non-TCP non-UDP protocols
Possibly even tools working with TCP and UDP

🔗 Input parameters

host
family

🔗 Output parameters

List of sockaddr pointers (zero ports, zero protocols, etc)
Canonical name (why?)

🔗 Current interface

Unfortunately, gethostbyname() has been deprecated and getaddrinfo() is not a good alternative.

🔗 Resolve a service name to a port number

Input parameters:

service
protocol (socktype?)

Output parameter:

port
protocol

Current status:

struct servent *getservbyname(const char *name, const char *proto);

struct servent {
    char  *s_name;       /* official service name */
    char **s_aliases;    /* alias list */
    int    s_port;       /* port number */
    char  *s_proto;      /* protocol to use */
}

🔗 Resolve an address for connect() or sendto()

Input parameters (network layer):

host (IP address or some sort of host name)
family (to implement -4 and -6 switches)

Input parameters (transport layer):

socktype
protocol
service (TCP/UDP port number or service name)
whether to use SRV records

Output parameters:

List of sockaddr pointers
Canonical name (why?)
socktype
protocol

🔗 Resolve an address for IP ACLs