зеркало из https://github.com/github/putty.git
Created a shiny new abstraction for the socket handling. Has many
advantages: - protocol modules can call sk_write() without having to worry about writes blocking, because blocking writes are handled in the abstraction layer and retried later. - `Lost connection while sending' is a thing of the past. - <winsock.h> is no longer needed in most modules, because "putty.h" doesn't have to declare `SOCKET' variables any more, only the abstracted `Socket' type. - select()-equivalent between multiple sockets will now be handled sensibly, which opens the way for things like SSH port forwarding. [originally from svn r745]
This commit is contained in:
Simon Tatham
Родитель
bbbda4110b
Коммит
988c1974ea
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@ -0,0 +1,44 @@
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/*
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* Networking abstraction in PuTTY.
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*
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* The way this works is: a back end can choose to open any number
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* of sockets - including zero, which might be necessary in some.
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* It can register a function to be called when data comes in on
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* any given one, and it can call the networking abstraction to
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* send data without having to worry about blocking. The stuff
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* behind the abstraction takes care of selects and nonblocking
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* writes and all that sort of painful gubbins.
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*
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* If urgent data comes in on a socket, the back end will read and
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* discard up to the urgent pointer, then read the urgent byte and
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* send _that_ to the receiver function with `urgent' set.
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*/
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typedef struct Socket_tag *Socket;
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typedef struct SockAddr_tag *SockAddr;
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typedef int (*sk_receiver_t)(Socket s, int urgent, char *data, int len);
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void sk_init(void); /* called once at program startup */
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SockAddr sk_namelookup(char *host, char **canonicalname);
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void sk_addr_free(SockAddr addr);
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Socket sk_new(SockAddr addr, int port, sk_receiver_t receiver);
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void sk_close(Socket s);
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void sk_write(Socket s, char *buf, int len);
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void sk_write_oob(Socket s, char *buf, int len);
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/*
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* Each socket abstraction contains a `void *' private field in
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* which the client can keep state.
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*/
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void sk_set_private_ptr(Socket s, void *ptr);
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void *sk_get_private_ptr(Socket s);
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/*
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* Special error values are returned from sk_namelookup and sk_new
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* if there's a problem. These functions extract an error message,
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* or return NULL if there's no problem.
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*/
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char *sk_addr_error(SockAddr addr);
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char *sk_socket_error(Socket addr);
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@ -0,0 +1,431 @@
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/*
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* Windows networking abstraction.
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*/
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#include <windows.h>
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#include <winsock.h>
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#include <stdio.h>
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#include "putty.h"
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#include "network.h"
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#include "tree234.h"
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#define BUFFER_GRANULE 512
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struct Socket_tag {
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char *error;
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SOCKET s;
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sk_receiver_t receiver;
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void *private_ptr;
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struct buffer *head, *tail;
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int writable;
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int in_oob, sending_oob;
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};
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struct SockAddr_tag {
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char *error;
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unsigned long address;
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};
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struct buffer {
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struct buffer *next;
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int buflen, bufpos;
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char buf[BUFFER_GRANULE];
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};
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static tree234 *sktree;
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static int cmpfortree(void *av, void *bv) {
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Socket a = (Socket)av, b = (Socket)bv;
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unsigned long as = (unsigned long)a->s, bs = (unsigned long)b->s;
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if (as < bs) return -1;
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if (as > bs) return +1;
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return 0;
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}
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static int cmpforsearch(void *av, void *bv) {
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Socket b = (Socket)bv;
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unsigned long as = (unsigned long)av, bs = (unsigned long)b->s;
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if (as < bs) return -1;
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if (as > bs) return +1;
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return 0;
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}
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void sk_init(void) {
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sktree = newtree234(cmpfortree);
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}
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SockAddr sk_namelookup(char *host, char **canonicalname) {
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SockAddr ret = smalloc(sizeof(struct SockAddr_tag));
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unsigned long a;
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struct hostent *h;
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if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
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if ( (h = gethostbyname(host)) == NULL) {
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DWORD err = WSAGetLastError();
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ret->error = (err == WSAENETDOWN ? "Network is down" :
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err == WSAHOST_NOT_FOUND ? "Host does not exist" :
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err == WSATRY_AGAIN ? "Host not found" :
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"gethostbyname: unknown error");
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} else {
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ret->error = NULL;
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memcpy (&a, h->h_addr, sizeof(a));
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*canonicalname = h->h_name;
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}
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} else {
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*canonicalname = host;
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}
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ret->address = ntohl(a);
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return ret;
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}
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void sk_addr_free(SockAddr addr) {
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sfree(addr);
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}
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Socket sk_new(SockAddr addr, int port, sk_receiver_t receiver) {
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SOCKET s;
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SOCKADDR_IN a;
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DWORD err;
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char *errstr;
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Socket ret;
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extern char *do_select(SOCKET skt, int startup);
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/*
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* Create Socket structure.
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*/
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ret = smalloc(sizeof(struct Socket_tag));
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ret->error = NULL;
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ret->receiver = receiver;
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ret->head = ret->tail = NULL;
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ret->writable = 1; /* to start with */
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ret->in_oob = FALSE;
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/*
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* Open socket.
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*/
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s = socket(AF_INET, SOCK_STREAM, 0);
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ret->s = s;
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if (s == INVALID_SOCKET) {
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err = WSAGetLastError();
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ret->error = (err == WSAENETDOWN ? "Network is down" :
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err == WSAEAFNOSUPPORT ? "TCP/IP support not present" :
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"socket(): unknown error");
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return ret;
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}
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/*
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* Bind to local address.
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*/
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a.sin_family = AF_INET;
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a.sin_addr.s_addr = htonl(INADDR_ANY);
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a.sin_port = htons(0);
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if (bind (s, (struct sockaddr *)&a, sizeof(a)) == SOCKET_ERROR) {
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err = WSAGetLastError();
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ret->error = (err == WSAENETDOWN ? "Network is down" :
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"bind(): unknown error");
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return ret;
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}
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/*
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* Connect to remote address.
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*/
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a.sin_addr.s_addr = htonl(addr->address);
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a.sin_port = htons((short)port);
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if (connect (s, (struct sockaddr *)&a, sizeof(a)) == SOCKET_ERROR) {
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err = WSAGetLastError();
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ret->error = (err == WSAENETDOWN ? "Network is down" :
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err == WSAECONNREFUSED ? "Connection refused" :
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err == WSAENETUNREACH ? "Network is unreachable" :
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err == WSAEHOSTUNREACH ? "No route to host" :
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"connect(): unknown error");
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return ret;
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}
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/* Set up a select mechanism. This could be an AsyncSelect on a
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* window, or an EventSelect on an event object. */
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errstr = do_select(s, 1);
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if (errstr) {
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ret->error = errstr;
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return ret;
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}
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add234(sktree, ret);
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return ret;
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}
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void sk_close(Socket s) {
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del234(sktree, s);
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do_select(s->s, 0);
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closesocket(s->s);
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free(s);
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}
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char *winsock_error_string(int error) {
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switch (error) {
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case WSAEACCES: return "Network error: Permission denied";
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case WSAEADDRINUSE: return "Network error: Address already in use";
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case WSAEADDRNOTAVAIL: return "Network error: Cannot assign requested address";
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case WSAEAFNOSUPPORT: return "Network error: Address family not supported by protocol family";
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case WSAEALREADY: return "Network error: Operation already in progress";
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case WSAECONNABORTED: return "Network error: Software caused connection abort";
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case WSAECONNREFUSED: return "Network error: Connection refused";
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case WSAECONNRESET: return "Network error: Connection reset by peer";
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case WSAEDESTADDRREQ: return "Network error: Destination address required";
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case WSAEFAULT: return "Network error: Bad address";
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case WSAEHOSTDOWN: return "Network error: Host is down";
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case WSAEHOSTUNREACH: return "Network error: No route to host";
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case WSAEINPROGRESS: return "Network error: Operation now in progress";
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case WSAEINTR: return "Network error: Interrupted function call";
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case WSAEINVAL: return "Network error: Invalid argument";
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case WSAEISCONN: return "Network error: Socket is already connected";
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case WSAEMFILE: return "Network error: Too many open files";
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case WSAEMSGSIZE: return "Network error: Message too long";
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case WSAENETDOWN: return "Network error: Network is down";
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case WSAENETRESET: return "Network error: Network dropped connection on reset";
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case WSAENETUNREACH: return "Network error: Network is unreachable";
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case WSAENOBUFS: return "Network error: No buffer space available";
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case WSAENOPROTOOPT: return "Network error: Bad protocol option";
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case WSAENOTCONN: return "Network error: Socket is not connected";
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case WSAENOTSOCK: return "Network error: Socket operation on non-socket";
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case WSAEOPNOTSUPP: return "Network error: Operation not supported";
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case WSAEPFNOSUPPORT: return "Network error: Protocol family not supported";
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case WSAEPROCLIM: return "Network error: Too many processes";
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case WSAEPROTONOSUPPORT: return "Network error: Protocol not supported";
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case WSAEPROTOTYPE: return "Network error: Protocol wrong type for socket";
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case WSAESHUTDOWN: return "Network error: Cannot send after socket shutdown";
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case WSAESOCKTNOSUPPORT: return "Network error: Socket type not supported";
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case WSAETIMEDOUT: return "Network error: Connection timed out";
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case WSAEWOULDBLOCK: return "Network error: Resource temporarily unavailable";
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case WSAEDISCON: return "Network error: Graceful shutdown in progress";
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default: return "Unknown network error";
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}
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}
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/*
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* The function which tries to send on a socket once it's deemed
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* writable.
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*/
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void try_send(Socket s) {
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while (s->head) {
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int nsent;
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DWORD err;
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int len, urgentflag;
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if (s->sending_oob) {
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urgentflag = MSG_OOB;
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len = s->sending_oob;
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} else {
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urgentflag = 0;
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len = s->head->buflen - s->head->bufpos;
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}
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nsent = send(s->s, s->head->buf + s->head->bufpos, len, urgentflag);
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if (nsent <= 0) {
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err = (nsent < 0 ? WSAGetLastError() : 0);
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if (err == WSAEWOULDBLOCK) {
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/* Perfectly normal: we've sent all we can for the moment. */
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s->writable = FALSE;
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return;
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} else if (nsent == 0 ||
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err == WSAECONNABORTED ||
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err == WSAECONNRESET) {
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/*
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* FIXME. This will have to be done better when we
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* start managing multiple sockets (e.g. SSH port
|
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* forwarding), because if we get CONNRESET while
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* trying to write a particular forwarded socket
|
||||
* then it isn't necessarily the end of the world.
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* Ideally I'd like to pass the error code back to
|
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* somewhere the next select_result() will see it,
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* but that might be hard. Perhaps I should pass it
|
||||
* back to be queued in the Windows front end bit.
|
||||
*/
|
||||
fatalbox(winsock_error_string(err));
|
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} else {
|
||||
fatalbox(winsock_error_string(err));
|
||||
}
|
||||
} else {
|
||||
s->head->bufpos += nsent;
|
||||
if (s->sending_oob)
|
||||
s->sending_oob -= nsent;
|
||||
if (s->head->bufpos >= s->head->buflen) {
|
||||
struct buffer *tmp = s->head;
|
||||
s->head = tmp->next;
|
||||
free(tmp);
|
||||
if (!s->head)
|
||||
s->tail = NULL;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void sk_write(Socket s, char *buf, int len) {
|
||||
/*
|
||||
* Add the data to the buffer list on the socket.
|
||||
*/
|
||||
if (s->tail && s->tail->buflen < BUFFER_GRANULE) {
|
||||
int copylen = min(len, BUFFER_GRANULE - s->tail->buflen);
|
||||
memcpy(s->tail->buf + s->tail->buflen, buf, copylen);
|
||||
buf += copylen;
|
||||
len -= copylen;
|
||||
s->tail->buflen += copylen;
|
||||
}
|
||||
while (len > 0) {
|
||||
int grainlen = min(len, BUFFER_GRANULE);
|
||||
struct buffer *newbuf;
|
||||
newbuf = smalloc(sizeof(struct buffer));
|
||||
newbuf->bufpos = 0;
|
||||
newbuf->buflen = grainlen;
|
||||
memcpy(newbuf->buf, buf, grainlen);
|
||||
buf += grainlen;
|
||||
len -= grainlen;
|
||||
if (s->tail)
|
||||
s->tail->next = newbuf;
|
||||
else
|
||||
s->head = s->tail = newbuf;
|
||||
newbuf->next = NULL;
|
||||
s->tail = newbuf;
|
||||
}
|
||||
|
||||
/*
|
||||
* Now try sending from the start of the buffer list.
|
||||
*/
|
||||
if (s->writable)
|
||||
try_send(s);
|
||||
}
|
||||
|
||||
void sk_write_oob(Socket s, char *buf, int len) {
|
||||
/*
|
||||
* Replace the buffer list on the socket with the data.
|
||||
*/
|
||||
if (!s->head) {
|
||||
s->head = smalloc(sizeof(struct buffer));
|
||||
} else {
|
||||
struct buffer *walk = s->head->next;
|
||||
while (walk) {
|
||||
struct buffer *tmp = walk;
|
||||
walk = tmp->next;
|
||||
free(tmp);
|
||||
}
|
||||
}
|
||||
s->head->next = NULL;
|
||||
s->tail = s->head;
|
||||
s->head->buflen = len;
|
||||
memcpy(s->head->buf, buf, len);
|
||||
|
||||
/*
|
||||
* Set the Urgent marker.
|
||||
*/
|
||||
s->sending_oob = len;
|
||||
|
||||
/*
|
||||
* Now try sending from the start of the buffer list.
|
||||
*/
|
||||
if (s->writable)
|
||||
try_send(s);
|
||||
}
|
||||
|
||||
int select_result(WPARAM wParam, LPARAM lParam) {
|
||||
int ret;
|
||||
DWORD err;
|
||||
char buf[BUFFER_GRANULE];
|
||||
Socket s;
|
||||
int atmark;
|
||||
|
||||
/* wParam is the socket itself */
|
||||
s = find234(sktree, (void *)wParam, cmpforsearch);
|
||||
if (!s)
|
||||
return 1; /* boggle */
|
||||
|
||||
if ((err = WSAGETSELECTERROR(lParam)) != 0) {
|
||||
fatalbox(winsock_error_string(err));
|
||||
}
|
||||
|
||||
switch (WSAGETSELECTEVENT(lParam)) {
|
||||
case FD_READ:
|
||||
ret = recv(s->s, buf, sizeof(buf), 0);
|
||||
if (ret < 0) {
|
||||
err = WSAGetLastError();
|
||||
if (err == WSAEWOULDBLOCK) {
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (ret < 0) {
|
||||
fatalbox(winsock_error_string(err));
|
||||
} else {
|
||||
int type = s->in_oob ? 2 : 0;
|
||||
s->in_oob = FALSE;
|
||||
return s->receiver(s, type, buf, ret);
|
||||
}
|
||||
break;
|
||||
case FD_OOB:
|
||||
/*
|
||||
* Read all data up to the OOB marker, and send it to the
|
||||
* receiver with urgent==1 (OOB pending).
|
||||
*/
|
||||
atmark = 1;
|
||||
s->in_oob = TRUE;
|
||||
/* Some WinSock wrappers don't support this call, so we
|
||||
* deliberately don't check the return value. If the call
|
||||
* fails and does nothing, we will get back atmark==1,
|
||||
* which is good enough to keep going at least. */
|
||||
ioctlsocket(s->s, SIOCATMARK, &atmark);
|
||||
ret = recv(s->s, buf, sizeof(buf), MSG_OOB);
|
||||
if (ret <= 0) {
|
||||
fatalbox(ret == 0 ? "Internal networking trouble" :
|
||||
winsock_error_string(WSAGetLastError()));
|
||||
} else {
|
||||
return s->receiver(s, atmark ? 2 : 1, buf, ret);
|
||||
}
|
||||
break;
|
||||
case FD_WRITE:
|
||||
s->writable = 1;
|
||||
try_send(s);
|
||||
break;
|
||||
case FD_CLOSE:
|
||||
/* Signal a close on the socket. */
|
||||
return s->receiver(s, 0, NULL, 0);
|
||||
break;
|
||||
}
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* Each socket abstraction contains a `void *' private field in
|
||||
* which the client can keep state.
|
||||
*/
|
||||
void sk_set_private_ptr(Socket s, void *ptr) {
|
||||
s->private_ptr = ptr;
|
||||
}
|
||||
void *sk_get_private_ptr(Socket s) {
|
||||
return s->private_ptr;
|
||||
}
|
||||
|
||||
/*
|
||||
* Special error values are returned from sk_namelookup and sk_new
|
||||
* if there's a problem. These functions extract an error message,
|
||||
* or return NULL if there's no problem.
|
||||
*/
|
||||
char *sk_addr_error(SockAddr addr) {
|
||||
return addr->error;
|
||||
}
|
||||
char *sk_socket_error(Socket s) {
|
||||
return s->error;
|
||||
}
|
||||
|
||||
/*
|
||||
* For Plink: enumerate all sockets currently active.
|
||||
*/
|
||||
SOCKET first_socket(enum234 *e) {
|
||||
Socket s = first234(sktree, e);
|
||||
return s ? s->s : INVALID_SOCKET;
|
||||
}
|
||||
SOCKET next_socket(enum234 *e) {
|
||||
Socket s = next234(e);
|
||||
return s ? s->s : INVALID_SOCKET;
|
||||
}
|
||||
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