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⬅️ Previous capture (2023-12-28)
-=-=-=-=-=-=-
G'day!
Gemini, while simple, isn't quite that simple. All protocol commands and
responses are over TLS connections, so doing a send/recv on a raw
network socket will not work!
I'm not 100% sure on the best or simplest way to get a TLS stack going
in C, I've done some bits with OpenSSL, but it was not simple!
Cheers
--
Paul
On 19/8/20 11:57 pm, - wrote:
> Hello,
>
> I've started writing a client for Gemini protocol, but since I've never
been writing networking programs, I find myself at the dead end at the
moment. Please could someone help me? When I send a request and get a
response, the only thing I have in response is "gemini://" and nothing
else. The code is given below:
>
> #include <arpa/inet.h>
> #include <locale.h>
> #include <netdb.h>
> #include <netinet/in.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <unistd.h>
>
> #define STATUS_CODE_INPUT 10
> #define STATUS_CODE_SENSITIVE_INPUT 11
> #define STATUS_CODE_SUCCESS 20
> #define STATUS_CODE_REDIRECT_TEMP 30
> #define STATUS_CODE_REDIRECT_PERM 31
> #define STATUS_CODE_TEMP_FAILURE 40
> #define STATUS_CODE_SERVER_UNAVAILABLE 41
> #define STATUS_CODE_CGI_ERROR 42
> #define STATUS_CODE_PROXY_ERROR 43
> #define STATUS_CODE_SLOW_DOWN 44
> #define STATUS_CODE_PERM_FAILURE 50
> #define STATUS_CODE_NOT_FOUND 51
> #define STATUS_CODE_GONE 52
> #define STATUS_CODE_PROXY_REQUEST_REFUSED 53
> #define STATUS_CODE_BAD_REQUEST 59
> #define STATUS_CODE_CLIENT_CERT_REQUIRED 60
> #define STATUS_CODE_CERT_NO_AUTH 61
> #define STATUS_CODE_CERT_NOT_VALID 62
>
> #define GEMINI_PORT 1965
>
> int main() {
> char *locale;
> locale = setlocale(LC_ALL, "");
>
> int sockfd = socket(AF_INET, SOCK_STREAM, 0);
> if (sockfd < 0) {
> perror("socket");
> exit(1);
> }
> char *url = malloc(sizeof(char)*1024);
> strcpy(url, "gemini://gemini.circumlunar.space/\r\n");
> char rec_buf[1029] = {0};
> struct hostent *host_entry;
> host_entry = gethostbyname(url);
> struct sockaddr_in addr;
> addr.sin_family = AF_INET;
> addr.sin_port = htons(GEMINI_PORT);
> addr.sin_addr.s_addr = htonl(INADDR_ANY);
> int opt = 1;
> if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
> perror("setsockopt");
> exit(1);
> }
> if (bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
> perror("bind");
> exit(2);
> }
> if (connect(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
> perror("connect");
> exit(3);
> }
> send(sockfd, url, sizeof(url), 0);
> recv(sockfd, rec_buf, sizeof(rec_buf), 0);
> printf("%s\n", rec_buf);
> close(sockfd);
> shutdown(sockfd, SHUT_RDWR);
> free(url);
> return 0;
> }
>
>
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Hello,
I've started writing a client for Gemini protocol, but since I've never
been writing networking programs, I find myself at the dead end at the
moment. Please could someone help me? When I send a request and get a
response, the only thing I have in response is "gemini://" and nothing
else. The code is given below:
#include <arpa/inet.h>
#include <locale.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#define STATUS_CODE_INPUT 10
#define STATUS_CODE_SENSITIVE_INPUT 11
#define STATUS_CODE_SUCCESS 20
#define STATUS_CODE_REDIRECT_TEMP 30
#define STATUS_CODE_REDIRECT_PERM 31
#define STATUS_CODE_TEMP_FAILURE 40
#define STATUS_CODE_SERVER_UNAVAILABLE 41
#define STATUS_CODE_CGI_ERROR 42
#define STATUS_CODE_PROXY_ERROR 43
#define STATUS_CODE_SLOW_DOWN 44
#define STATUS_CODE_PERM_FAILURE 50
#define STATUS_CODE_NOT_FOUND 51
#define STATUS_CODE_GONE 52
#define STATUS_CODE_PROXY_REQUEST_REFUSED 53
#define STATUS_CODE_BAD_REQUEST 59
#define STATUS_CODE_CLIENT_CERT_REQUIRED 60
#define STATUS_CODE_CERT_NO_AUTH 61
#define STATUS_CODE_CERT_NOT_VALID 62
#define GEMINI_PORT 1965
int main() {
char *locale;
locale = setlocale(LC_ALL, "");
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) {
perror("socket");
exit(1);
}
char *url = malloc(sizeof(char)*1024);
strcpy(url, "gemini://gemini.circumlunar.space/\r\n");
char rec_buf[1029] = {0};
struct hostent *host_entry;
host_entry = gethostbyname(url);
struct sockaddr_in addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(GEMINI_PORT);
addr.sin_addr.s_addr = htonl(INADDR_ANY);
int opt = 1;
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
perror("setsockopt");
exit(1);
}
if (bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
perror("bind");
exit(2);
}
if (connect(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
perror("connect");
exit(3);
}
send(sockfd, url, sizeof(url), 0);
recv(sockfd, rec_buf, sizeof(rec_buf), 0);
printf("%s\n", rec_buf);
close(sockfd);
shutdown(sockfd, SHUT_RDWR);
free(url);
return 0;
}
--
- <anridellal at yandex.ru>
This is something I had been tinkering with, before getting distracted
onto something else(!). I found two examples of simple echo servers,
one for GnuTLS and one OpenSSL. The code is here
gemini://gemini.susa.net/c/
Both certainly compiled (I have binaries on disk), but I can't recall
any more detail than that, so just sharing this as a pointer to the
original poster.
Kevin
On Wed, 19 Aug 2020 at 12:36, Paul Warren <pwarren at pwarren.id.au> wrote:
>
> G'day!
>
> Gemini, while simple, isn't quite that simple. All protocol commands and
> responses are over TLS connections, so doing a send/recv on a raw
> network socket will not work!
>
> I'm not 100% sure on the best or simplest way to get a TLS stack going
> in C, I've done some bits with OpenSSL, but it was not simple!
>
> Cheers
> --
> Paul
>
>
>
> On 19/8/20 11:57 pm, - wrote:
> > Hello,
> >
> > I've started writing a client for Gemini protocol, but since I've
never been writing networking programs, I find myself at the dead end at
the moment. Please could someone help me? When I send a request and get a
response, the only thing I have in response is "gemini://" and nothing
else. The code is given below:
> >
> > #include <arpa/inet.h>
> > #include <locale.h>
> > #include <netdb.h>
> > #include <netinet/in.h>
> > #include <stdio.h>
> > #include <stdlib.h>
> > #include <string.h>
> > #include <sys/types.h>
> > #include <sys/socket.h>
> > #include <unistd.h>
> >
> > #define STATUS_CODE_INPUT 10
> > #define STATUS_CODE_SENSITIVE_INPUT 11
> > #define STATUS_CODE_SUCCESS 20
> > #define STATUS_CODE_REDIRECT_TEMP 30
> > #define STATUS_CODE_REDIRECT_PERM 31
> > #define STATUS_CODE_TEMP_FAILURE 40
> > #define STATUS_CODE_SERVER_UNAVAILABLE 41
> > #define STATUS_CODE_CGI_ERROR 42
> > #define STATUS_CODE_PROXY_ERROR 43
> > #define STATUS_CODE_SLOW_DOWN 44
> > #define STATUS_CODE_PERM_FAILURE 50
> > #define STATUS_CODE_NOT_FOUND 51
> > #define STATUS_CODE_GONE 52
> > #define STATUS_CODE_PROXY_REQUEST_REFUSED 53
> > #define STATUS_CODE_BAD_REQUEST 59
> > #define STATUS_CODE_CLIENT_CERT_REQUIRED 60
> > #define STATUS_CODE_CERT_NO_AUTH 61
> > #define STATUS_CODE_CERT_NOT_VALID 62
> >
> > #define GEMINI_PORT 1965
> >
> > int main() {
> > char *locale;
> > locale = setlocale(LC_ALL, "");
> >
> > int sockfd = socket(AF_INET, SOCK_STREAM, 0);
> > if (sockfd < 0) {
> > perror("socket");
> > exit(1);
> > }
> > char *url = malloc(sizeof(char)*1024);
> > strcpy(url, "gemini://gemini.circumlunar.space/\r\n");
> > char rec_buf[1029] = {0};
> > struct hostent *host_entry;
> > host_entry = gethostbyname(url);
> > struct sockaddr_in addr;
> > addr.sin_family = AF_INET;
> > addr.sin_port = htons(GEMINI_PORT);
> > addr.sin_addr.s_addr = htonl(INADDR_ANY);
> > int opt = 1;
> > if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
> > perror("setsockopt");
> > exit(1);
> > }
> > if (bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
> > perror("bind");
> > exit(2);
> > }
> > if (connect(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
> > perror("connect");
> > exit(3);
> > }
> > send(sockfd, url, sizeof(url), 0);
> > recv(sockfd, rec_buf, sizeof(rec_buf), 0);
> > printf("%s\n", rec_buf);
> > close(sockfd);
> > shutdown(sockfd, SHUT_RDWR);
> > free(url);
> > return 0;
> > }
> >
> >
>
I think I misread some parts of specification. Thank you very much.
On Wed, 19 Aug 2020 21:36:18 +1000
Paul Warren <pwarren at pwarren.id.au> wrote:
> G'day!
>
> Gemini, while simple, isn't quite that simple. All protocol commands and
> responses are over TLS connections, so doing a send/recv on a raw
> network socket will not work!
>
> I'm not 100% sure on the best or simplest way to get a TLS stack going
> in C, I've done some bits with OpenSSL, but it was not simple!
>
> Cheers
> --
> Paul
>
>
>
> On 19/8/20 11:57 pm, - wrote:
> > Hello,
> >
> > I've started writing a client for Gemini protocol, but since I've
never been writing networking programs, I find myself at the dead end at
the moment. Please could someone help me? When I send a request and get a
response, the only thing I have in response is "gemini://" and nothing
else. The code is given below:
> >
> > #include <arpa/inet.h>
> > #include <locale.h>
> > #include <netdb.h>
> > #include <netinet/in.h>
> > #include <stdio.h>
> > #include <stdlib.h>
> > #include <string.h>
> > #include <sys/types.h>
> > #include <sys/socket.h>
> > #include <unistd.h>
> >
> > #define STATUS_CODE_INPUT 10
> > #define STATUS_CODE_SENSITIVE_INPUT 11
> > #define STATUS_CODE_SUCCESS 20
> > #define STATUS_CODE_REDIRECT_TEMP 30
> > #define STATUS_CODE_REDIRECT_PERM 31
> > #define STATUS_CODE_TEMP_FAILURE 40
> > #define STATUS_CODE_SERVER_UNAVAILABLE 41
> > #define STATUS_CODE_CGI_ERROR 42
> > #define STATUS_CODE_PROXY_ERROR 43
> > #define STATUS_CODE_SLOW_DOWN 44
> > #define STATUS_CODE_PERM_FAILURE 50
> > #define STATUS_CODE_NOT_FOUND 51
> > #define STATUS_CODE_GONE 52
> > #define STATUS_CODE_PROXY_REQUEST_REFUSED 53
> > #define STATUS_CODE_BAD_REQUEST 59
> > #define STATUS_CODE_CLIENT_CERT_REQUIRED 60
> > #define STATUS_CODE_CERT_NO_AUTH 61
> > #define STATUS_CODE_CERT_NOT_VALID 62
> >
> > #define GEMINI_PORT 1965
> >
> > int main() {
> > char *locale;
> > locale = setlocale(LC_ALL, "");
> >
> > int sockfd = socket(AF_INET, SOCK_STREAM, 0);
> > if (sockfd < 0) {
> > perror("socket");
> > exit(1);
> > }
> > char *url = malloc(sizeof(char)*1024);
> > strcpy(url, "gemini://gemini.circumlunar.space/\r\n");
> > char rec_buf[1029] = {0};
> > struct hostent *host_entry;
> > host_entry = gethostbyname(url);
> > struct sockaddr_in addr;
> > addr.sin_family = AF_INET;
> > addr.sin_port = htons(GEMINI_PORT);
> > addr.sin_addr.s_addr = htonl(INADDR_ANY);
> > int opt = 1;
> > if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
> > perror("setsockopt");
> > exit(1);
> > }
> > if (bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
> > perror("bind");
> > exit(2);
> > }
> > if (connect(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
> > perror("connect");
> > exit(3);
> > }
> > send(sockfd, url, sizeof(url), 0);
> > recv(sockfd, rec_buf, sizeof(rec_buf), 0);
> > printf("%s\n", rec_buf);
> > close(sockfd);
> > shutdown(sockfd, SHUT_RDWR);
> > free(url);
> > return 0;
> > }
> >
> >
>
--
- <anridellal at yandex.ru>
Thank you.
I managed to make it work with LibreSSL's libtls:
https://man.openbsd.org/tls_init.3
Sharing the code in case someone wants to take a look at an implementation
(the code is far from perfection, but I'll fix it later):
#include <arpa/inet.h>
#include <locale.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <tls.h>
#include <unistd.h>
#define STATUS_CODE_INPUT "10"
#define STATUS_CODE_SENSITIVE_INPUT "11"
#define STATUS_CODE_SUCCESS "20"
#define STATUS_CODE_REDIRECT_TEMP "30"
#define STATUS_CODE_REDIRECT_PERM "31"
#define STATUS_CODE_TEMP_FAILURE "40"
#define STATUS_CODE_SERVER_UNAVAILABLE "41"
#define STATUS_CODE_CGI_ERROR "42"
#define STATUS_CODE_PROXY_ERROR "43"
#define STATUS_CODE_SLOW_DOWN "44"
#define STATUS_CODE_PERM_FAILURE "50"
#define STATUS_CODE_NOT_FOUND "51"
#define STATUS_CODE_GONE "52"
#define STATUS_CODE_PROXY_REQUEST_REFUSED "53"
#define STATUS_CODE_BAD_REQUEST "59"
#define STATUS_CODE_CLIENT_CERT_REQUIRED "60"
#define STATUS_CODE_CERT_NO_AUTH "61"
#define STATUS_CODE_CERT_NOT_VALID "62"
#define GEMINI_PORT "1965"
int main() {
char *locale;
locale = setlocale(LC_ALL, "");
tls_init();
struct tls_config *tlsconf = tls_config_new();
struct tls *client = tls_client();
tls_config_set_protocols(tlsconf, TLS_PROTOCOL_TLSv1_3);
tls_configure(client, tlsconf);
const char *hostname = "gemini.circumlunar.space";
char *url = malloc(sizeof(char)*1024);
strcpy(url, "gemini://gemini.circumlunar.space/");
char rec_buf[1029];
int writebytes = sprintf(url, "%s\r\n", url);
tls_connect(client, hostname, GEMINI_PORT);
while (writebytes > 0) {
ssize_t outbytes;
outbytes = tls_write(client, url, (size_t)writebytes);
if (outbytes == TLS_WANT_POLLIN || outbytes == TLS_WANT_POLLOUT)
continue;
if (outbytes == -1) {
perror("tls_write");
}
url += outbytes;
writebytes -= outbytes;
}
// read header
tls_read(client, rec_buf, sizeof(rec_buf));
printf("%s\n", rec_buf);
char status_code[3];
strncpy(status_code, rec_buf, 2);
if (strcmp(status_code, STATUS_CODE_SUCCESS) == 0) {
writebytes = tls_read(client, rec_buf, (size_t)sizeof(rec_buf));
printf("%d\n", writebytes);
while (writebytes > 0) {
printf(rec_buf);
writebytes = tls_read(client, rec_buf, (size_t)writebytes);
printf("\n%d\n", writebytes);
}
printf("\r\n");
}
tls_close(client);
tls_free(client);
return 0;
}
On Wed, 19 Aug 2020 15:55:00 +0100
Kevin Sangeelee <kevin at susa.net> wrote:
> This is something I had been tinkering with, before getting distracted
> onto something else(!). I found two examples of simple echo servers,
> one for GnuTLS and one OpenSSL. The code is here
>
> gemini://gemini.susa.net/c/
>
> Both certainly compiled (I have binaries on disk), but I can't recall
> any more detail than that, so just sharing this as a pointer to the
> original poster.
>
> Kevin
>
> On Wed, 19 Aug 2020 at 12:36, Paul Warren <pwarren at pwarren.id.au> wrote:
> >
> > G'day!
> >
> > Gemini, while simple, isn't quite that simple. All protocol commands and
> > responses are over TLS connections, so doing a send/recv on a raw
> > network socket will not work!
> >
> > I'm not 100% sure on the best or simplest way to get a TLS stack going
> > in C, I've done some bits with OpenSSL, but it was not simple!
> >
> > Cheers
> > --
> > Paul
> >
> >
> >
> > On 19/8/20 11:57 pm, - wrote:
> > > Hello,
> > >
> > > I've started writing a client for Gemini protocol, but since I've
never been writing networking programs, I find myself at the dead end at
the moment. Please could someone help me? When I send a request and get a
response, the only thing I have in response is "gemini://" and nothing
else. The code is given below:
> > >
> > > #include <arpa/inet.h>
> > > #include <locale.h>
> > > #include <netdb.h>
> > > #include <netinet/in.h>
> > > #include <stdio.h>
> > > #include <stdlib.h>
> > > #include <string.h>
> > > #include <sys/types.h>
> > > #include <sys/socket.h>
> > > #include <unistd.h>
> > >
> > > #define STATUS_CODE_INPUT 10
> > > #define STATUS_CODE_SENSITIVE_INPUT 11
> > > #define STATUS_CODE_SUCCESS 20
> > > #define STATUS_CODE_REDIRECT_TEMP 30
> > > #define STATUS_CODE_REDIRECT_PERM 31
> > > #define STATUS_CODE_TEMP_FAILURE 40
> > > #define STATUS_CODE_SERVER_UNAVAILABLE 41
> > > #define STATUS_CODE_CGI_ERROR 42
> > > #define STATUS_CODE_PROXY_ERROR 43
> > > #define STATUS_CODE_SLOW_DOWN 44
> > > #define STATUS_CODE_PERM_FAILURE 50
> > > #define STATUS_CODE_NOT_FOUND 51
> > > #define STATUS_CODE_GONE 52
> > > #define STATUS_CODE_PROXY_REQUEST_REFUSED 53
> > > #define STATUS_CODE_BAD_REQUEST 59
> > > #define STATUS_CODE_CLIENT_CERT_REQUIRED 60
> > > #define STATUS_CODE_CERT_NO_AUTH 61
> > > #define STATUS_CODE_CERT_NOT_VALID 62
> > >
> > > #define GEMINI_PORT 1965
> > >
> > > int main() {
> > > char *locale;
> > > locale = setlocale(LC_ALL, "");
> > >
> > > int sockfd = socket(AF_INET, SOCK_STREAM, 0);
> > > if (sockfd < 0) {
> > > perror("socket");
> > > exit(1);
> > > }
> > > char *url = malloc(sizeof(char)*1024);
> > > strcpy(url, "gemini://gemini.circumlunar.space/\r\n");
> > > char rec_buf[1029] = {0};
> > > struct hostent *host_entry;
> > > host_entry = gethostbyname(url);
> > > struct sockaddr_in addr;
> > > addr.sin_family = AF_INET;
> > > addr.sin_port = htons(GEMINI_PORT);
> > > addr.sin_addr.s_addr = htonl(INADDR_ANY);
> > > int opt = 1;
> > > if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
> > > perror("setsockopt");
> > > exit(1);
> > > }
> > > if (bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
> > > perror("bind");
> > > exit(2);
> > > }
> > > if (connect(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
> > > perror("connect");
> > > exit(3);
> > > }
> > > send(sockfd, url, sizeof(url), 0);
> > > recv(sockfd, rec_buf, sizeof(rec_buf), 0);
> > > printf("%s\n", rec_buf);
> > > close(sockfd);
> > > shutdown(sockfd, SHUT_RDWR);
> > > free(url);
> > > return 0;
> > > }
> > >
> > >
> >
--
- <anridellal at yandex.ru>
---