# install rpcbing & tirpc (transport-independant RPC library)
$ sudo apt install rpcbind rpcsvc-proto libtirpc-dev libtirpc3
$ rpcinfo -p
program vers proto port service
100000 4 tcp 111 portmapper
100000 3 tcp 111 portmapper
100000 2 tcp 111 portmapper
100000 4 udp 111 portmapper
100000 3 udp 111 portmapper
100000 2 udp 111 portmapperGiven the interface add.x, we can generate all the files including
sample code for client and server side by using rpcgen.
$ rpcgen -a -N add.xAccording to manual, the option -N is for the newstyle of rpcgen. This allows
procedures to have multiple arguments. It also uses the style of parameter
passing that closely resembles C. So, when passing an argument to a remote
procedure you do not have to pass a pointer to the argument but the argument
it‐self. This behaviour is different from the oldstyle of rpcgen generated
code. The newstyle is not the default case because of backward compatibility.
In this demo, we provide no implementation for the add program, but just a
Makefile to compile the sample code with library tirpc.
This demo shows the implementation of the add program, by using client &
server stubs that are generated by rpcgen.
In this demo, we do some refactoring compared to the previous demo, and we only
use rpcgen to generate the header add.h.
This demo illustrates how to implement client and server directly without using
client & server stubs that are generated by rpcgen. This code is more simple
to understand than the previous one. It illustrates how to use directly RPC API.
Nota Bene : The add program number defined in add.x is
0x20000199=536871321.
Let's try to launch this demo...
# compilation
$ cd demo-03
$ make
gcc -std=c99 -I /usr/include/tirpc/ -c -o server.o server.c
gcc server.o -o server -ltirpc
gcc -std=c99 -I /usr/include/tirpc/ -c -o client.o client.c
gcc client.o -o client -ltirpc
# launch server for add program
$ ./server
# list registered services (in another terminal)
$ rpcinfo -p
program vers proto port service
100000 4 tcp 111 portmapper
100000 3 tcp 111 portmapper
100000 2 tcp 111 portmapper
100000 4 udp 111 portmapper
100000 3 udp 111 portmapper
100000 2 udp 111 portmapper
536871321 1 tcp 52466 # <-- our service for tcp
536871321 1 udp 57331 # <-- our service for udp
# launch client (in another terminal)
$ ./client localhost
result: 10 + 20 = 30As the previous one, this demo illustrates how to implement client and server directly with RPC API. It provides a bit more complex program test.x with more procedures. Besides, the server can manage its own socket and can optionally bind it to a given port, instead of choosing one randomly.
Nota Bene : The test program number defined in test.x is 0x20000001=536870913.
Let's try to launch this demo... Here, the client uses the UDP transport layer
to call both add and echo procedures.
# compilation
$ cd demo-04
$ make
gcc -std=c99 -Wall -g -I /usr/include/tirpc/ -c -o server.o server.c
gcc server.o -o server -ltirpc
gcc -std=c99 -Wall -g -I /usr/include/tirpc/ -c -o client.o client.c
gcc client.o -o client -ltirpc
# launch server for test program (listening on port 7777)
$ ./server 7777
# list registered services (in another terminal)
$ rpcinfo -p
program vers proto port service
100000 4 tcp 111 portmapper
100000 3 tcp 111 portmapper
100000 2 tcp 111 portmapper
100000 4 udp 111 portmapper
100000 3 udp 111 portmapper
100000 2 udp 111 portmapper
536870913 1 tcp 7777 # <-- our service for tcp
536870913 1 udp 7777 # <-- our service for udp
# launch client (in another terminal)
$ ./client localhost
add result: 10 + 20 = 30
echo result: helloHere, we have the same demo as the previous one, but we remove the use of
rpcbind for both client and server. So that, the client is directly connected
to the RPC server. This code is only available for UDP transport layer.
# compilation
$ cd demo-05
$ make
# launch server for test program (listening on port 7777)
$ ./server 7777
# launch client (in another terminal)
$ ./client localhost 7777
add result: 10 + 20 = 30
echo result: helloIf wireshark doesn't know the program number, it doesn't do the RPC decode, unless "Dissect unknown RPC program numbers" is checked in the preferences. After this, you can see both the request and replies.
Here are the capture of the RPC demo with both UDP & TCP transport layers :
- ONC/SUN RPC: http://en.wikipedia.org/wiki/ONC_RPC
- RFC 1831 RPC: Remote Procedure Call Protocol Version 2
- RFC 1832 XDR: External Data Representation Standard
- RFC 1833 Port Mapper: Binding Protocols for ONC RPC Version 2