https://github.com/jiseoup/rpc_raspberrypi
RPC(Remote Procedure Call) between raspberry pi.
https://github.com/jiseoup/rpc_raspberrypi
Last synced: about 2 months ago
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RPC(Remote Procedure Call) between raspberry pi.
- Host: GitHub
- URL: https://github.com/jiseoup/rpc_raspberrypi
- Owner: Jiseoup
- Created: 2022-08-09T08:04:19.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2022-08-11T09:28:10.000Z (almost 3 years ago)
- Last Synced: 2025-02-09T08:28:53.435Z (4 months ago)
- Language: C
- Size: 92.8 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# RPC BETWEEN RASPBERRY PI 
This document describes the **Remote Procedure Call(RPC)** between `Raspberry Pi`.
I recommend you to read [this document](https://github.com/Jiseoup/rpi_fixed_ip) and allocate fixed ip to `Raspberry Pi` before doing this.
## 1. REQUIRED INSTALLATION
We install and use the **rpcbind** package.
Packages **nfs-common** and **nfs-kernel-server** are needed to use RPC.
```console
$ sudo apt-get update
$ sudo apt-get install rpcbind
$ sudo apt-get install nfs-common
$ sudo apt-get install nfs-kernel-server
```
You can check your RPC information through the command below.
```console
pi@raspberrypi:~ $ rpcinfo
program version netid address service owner
100000 4 tcp6 ::.0.111 portmapper superuser
100000 3 tcp6 ::.0.111 portmapper superuser
100000 4 udp6 ::.0.111 portmapper superuser
100000 3 udp6 ::.0.111 portmapper superuser
100000 4 tcp 0.0.0.0.0.111 portmapper superuser
100000 3 tcp 0.0.0.0.0.111 portmapper superuser
100000 2 tcp 0.0.0.0.0.111 portmapper superuser
100000 4 udp 0.0.0.0.0.111 portmapper superuser
100000 3 udp 0.0.0.0.0.111 portmapper superuser
100000 2 udp 0.0.0.0.0.111 portmapper superuser
100000 4 local /run/rpcbind.sock portmapper superuser
100000 3 local /run/rpcbind.sock portmapper superuser
```
## 2. GENERATE CLIENT AND SERVER STUB
First, create the work directory and move to that directory.
```console
$ mkdir RPC
$ cd RPC
```
Now, we will create a file in `.x` format.
After that, we will generate a **stub** of the client and server through the `.x file` and **rpcgen**.
```console
$ vim rpc.x
```
### rpc.x
```xdr
program RPC_PROG {
version RPC_VERS {
int id(int)=1;
string name(string)=2;
}=1;
}=0x20000001;
```
### Generate Stub File
* -a : generate all files, including samples.
* -C : ANSI C mode.
```console
$ rpcgen -a -C rpc.x
```
You can see the generated stub file.
```console
pi@raspberrypi:~/RPC $ ls
Makefile.rpc rpc_client.c rpc_clnt.c rpc.h rpc_server.c rpc_svc.c rpc.x
```
## 3. EDIT CODES AND COMPILE
Edit the codes `rpc_server.c` and `rpc_client.c` and compile using `Makefile.rpc`.
Edit the code as below.
### rpc_server.c
```c
#include "rpc.h"
int *
id_1_svc(int *argp, struct svc_req *rqstp)
{
static int result;
result = *argp; // Assign the recalled data.
printf("INTEGER : %d is called\n", result);
return &result;
}
char **
name_1_svc(char **argp, struct svc_req *rqstp)
{
static char *result;
result = *argp; // Assign the recalled data.
printf("STRING : %s is called\n", result);
return &result;
}
```
### rpc_client.c
```c
#include "rpc.h"
void
rpc_prog_1(char *host, int a, char* b) // Add parameters. (int a, char* b)
{
CLIENT *clnt;
int *result_1;
int id_1_arg;
char * *result_2;
char * name_1_arg;
#ifndef DEBUG
clnt = clnt_create (host, RPC_PROG, RPC_VERS, "udp");
if (clnt == NULL) {
clnt_pcreateerror (host);
exit (1);
}
#endif /* DEBUG */
// Assigns the data to be called to a variable.
id_1_arg = a;
name_1_arg = b;
result_1 = id_1(&id_1_arg, clnt);
if (result_1 == (int *) NULL) {
clnt_perror (clnt, "call failed");
}
// When the call is successful.
else {
printf("INTEGER : %d\n", *result_1);
}
result_2 = name_1(&name_1_arg, clnt);
if (result_2 == (char **) NULL) {
clnt_perror (clnt, "call failed");
}
// When the call is successful.
else{
printf("STRING : %s\n", *result_2);
}
#ifndef DEBUG
clnt_destroy (clnt);
#endif /* DEBUG */
}
int
main (int argc, char *argv[])
{
char *host;
// Because we added two parameters, change the condition to (argc < 4).
if (argc < 4) {
printf ("usage: %s server_host INTEGER STRING\n", argv[0]);
exit (1);
}
host = argv[1];
rpc_prog_1 (host, atoi(argv[2]), argv[3]);
exit (0);
}
```
When you have finished editing the code, compile it using the command below.
* -f : Read FILE as a makefile.
* -f FILE, --file=FILE, --makefile=FILE
```console
$ make -f Makefile.rpc
```
You can see the generated files.
```console
pi@raspberrypi:~/RPC $ ls
Makefile.rpc rpc_client.c rpc_clnt.c rpc.h rpc_server.c rpc_svc.c rpc.x
rpc_client rpc_client.o rpc_clnt.o rpc_server rpc_server.o rpc_svc.o
```
## 4. TEST THE SAMPLE CODE
We test the sample code on one `Raspberry Pi`.
Of course, **RPC calls** from different `Raspberry Pi` are also possible.
### Usage
* Server
```console
$ ./rpc_server
```
* Client
```console
$ ./rpc_client {ip_address} {integer} {string}
```
Open two terminals and call the `localhost` server from the client as shown in the picture below.
Run the server first, then run the client.
