[9fans] dial M for Minimalism

[9fans] dial M for Minimalism

[Nigel]

as a doctor, i am often asked ``why doesn't Plan 9 (or Inferno) use
the `standard' socket calls?''

Shurley some mishqoute here (ed)?

[9fans] dial M for Minimalism

[@ 1998-12-10 10:19 UTC (permalink / raw)]

forsyth@caldo.demon.co.uk wrote:

> as a doctor, i am often asked ``why doesn't Plan 9 (or Inferno) use
> the `standard' socket calls?''
>
> the source of tcpblast.c was recently posted to this list.
> it makes a tcp/ip call to a given machine.
> the bits that do so are shown below (i have completed
> the code that looks up the service name):
>
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <netinet/in.h>
> #include <netdb.h>
>
>         ...
>
> struct sockaddr_in sock_in;
> struct servent *sp;
> struct hostent *host;
>
>         ...
>  memset(&sock_in, 0, sizeof (sock_in));
>  sock_in.sin_family = AF_INET;
>  f = socket(AF_INET, SOCK_STREAM, 0);
>  if (f < 0) {
>   perror("tcpblast: socket");
>   exit(3);
>  }
>  if (bind(f, (struct sockaddr*) &sock_in, sizeof (sock_in)) < 0) {
>   perror("tcpblast: bind");
>   exit(1);
>  }
>
>  host = gethostbyname(argv[1]);
>  if (host) {
>   sock_in.sin_family = host->h_addrtype;
>   memmove(&sock_in.sin_addr, host->h_addr, host->h_length);
>  } else {
>   sock_in.sin_family = AF_INET;
>   sock_in.sin_addr.s_addr = inet_addr(argv[1]);
>   if (sock_in.sin_addr.s_addr == -1) {
>    fprintf(stderr, "tcpblast: %s unknown host\n", argv[1]);
>    exit(1);
>   }
>  }
>  sp = getservbyname("discard", "tcp");
>  if (sp)
>    sock_in.sin_port = sp->s_port;
>  else
>    sock_in.sin_port = htons(9);
>
>  if (connect(f, (struct sockaddr*) &sock_in, sizeof(sock_in)) <0)
>  {
>   perror("tcpblast connect:");
>   exit(1);
>  }
>
> by contrast, in my variant for Plan 9, i wrote:
>
> #include <u.h>
> #include <libc.h>
>
>         ...
>
>         fd = dial(netmkaddr(argv[0], "tcp", "discard"), nil, nil, nil);
>         if(fd < 0){
>                 fprint(2, "tcpbuzz: can't dial %s: %r\n", argv[0]);
>                 exits("dial");
>         }
>
> the nil, nil, nil looks and sounds like a Eurovision Song Contest
> score, which is perhaps a blemish.  (each nil represents a default
> that more specialised applications can set to access such things as
> port number assignment and the connection's control and status files.
> Inferno's dial interface is simpler still, partly because of the use
> of Limbo tuples.)  apart from that, the incantation is straightforward
> and easy to write.  because the interface and underlying
> infrastructure provides a good degree of abstraction, it also works
> without change for all suitable network types and protocols; it isn't
> limited to TCP/IP or IP networks.  the connection service and name
> space together sort out the details; that the network files live in
> the per-process name space also enables the same code to dial through
> an imported gateway.

[9fans] dial M for Minimalism

[forsyth]

as a doctor, i am often asked ``why doesn't Plan 9 (or Inferno) use
the `standard' socket calls?''

the source of tcpblast.c was recently posted to this list.
it makes a tcp/ip call to a given machine.
the bits that do so are shown below (i have completed
the code that looks up the service name):

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

	...

struct sockaddr_in sock_in;
struct servent *sp;
struct hostent *host;

	...
 memset(&sock_in, 0, sizeof (sock_in));
 sock_in.sin_family = AF_INET;
 f = socket(AF_INET, SOCK_STREAM, 0);
 if (f < 0) {
  perror("tcpblast: socket");
  exit(3);
 }
 if (bind(f, (struct sockaddr*) &sock_in, sizeof (sock_in)) < 0) {
  perror("tcpblast: bind");
  exit(1);
 }

 host = gethostbyname(argv[1]);
 if (host) {
  sock_in.sin_family = host->h_addrtype;
  memmove(&sock_in.sin_addr, host->h_addr, host->h_length);
 } else {
  sock_in.sin_family = AF_INET;
  sock_in.sin_addr.s_addr = inet_addr(argv[1]);
  if (sock_in.sin_addr.s_addr == -1) {
   fprintf(stderr, "tcpblast: %s unknown host\n", argv[1]);
   exit(1);
  }
 }
 sp = getservbyname("discard", "tcp");
 if (sp)
   sock_in.sin_port = sp->s_port;
 else
   sock_in.sin_port = htons(9);

 if (connect(f, (struct sockaddr*) &sock_in, sizeof(sock_in)) <0)
 {
  perror("tcpblast connect:");
  exit(1);
 }

by contrast, in my variant for Plan 9, i wrote:

#include <u.h>
#include <libc.h>

	...

	fd = dial(netmkaddr(argv[0], "tcp", "discard"), nil, nil, nil);
	if(fd < 0){
		fprint(2, "tcpbuzz: can't dial %s: %r\n", argv[0]);
		exits("dial");
	}

the nil, nil, nil looks and sounds like a Eurovision Song Contest
score, which is perhaps a blemish.  (each nil represents a default
that more specialised applications can set to access such things as
port number assignment and the connection's control and status files.
Inferno's dial interface is simpler still, partly because of the use
of Limbo tuples.)  apart from that, the incantation is straightforward
and easy to write.  because the interface and underlying
infrastructure provides a good degree of abstraction, it also works
without change for all suitable network types and protocols; it isn't
limited to TCP/IP or IP networks.  the connection service and name
space together sort out the details; that the network files live in
the per-process name space also enables the same code to dial through
an imported gateway.