corkscrewをSSLなプロキシに対応させた ref: http://qiita.com/komeda-shinji/items/8a78f07cc7d0d75d37c0

file0.txt

usage: corkscrew [-ssl] <proxyhost> <proxyport> <desthost> <destport> [authfile]

file1.txt

make LDADD="-lcrypto -lssl"

file2.diff

% diff -u corkscrew-2.0/corkscrew.c corkscrew-2.0/corkscrew.c 
--- corkscrew-2.0/corkscrew.c   2001-08-24 03:27:32.000000000 +0900
+++ corkscrew-2.0/corkscrew.c   2014-11-11 19:35:08.000000000 +0900
@@ -12,6 +12,12 @@
 #include <sys/types.h>
 #include <unistd.h>

+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+
+#define CHK_NULL(x) if ((x)==NULL) { fprintf(stderr, "NULL pointer\n"); exit(-1); }
+
 #if HAVE_SYS_FILIO_H
 #include <sys/filio.h>
 #endif
@@ -27,7 +33,7 @@

 char *base64_encodei PARAMS((char *in));
 void usage PARAMS((void));
-int sock_connect PARAMS((const char *hname, int port));
+int sock_connect PARAMS((int fd, const char *hname, int port));
 int main PARAMS((int argc, char *argv[]));

 #define BUFSIZE 4096
@@ -132,21 +138,17 @@
 }

 #ifdef ANSI_FUNC
-int sock_connect (const char *hname, int port)
+int sock_connect (int fd, const char *hname, int port)
 #else
-int sock_connect (hname, port)
+int sock_connect (fd, hname, port)
+int fd;
 const char *hname;
 int port;
 #endif
 {
-   int fd;
    struct sockaddr_in addr;
    struct hostent *hent;

-   fd = socket(AF_INET, SOCK_STREAM, 0);
-   if (fd == -1)
-       return -1;
-
    hent = gethostbyname(hname);
    if (hent == NULL)
        addr.sin_addr.s_addr = inet_addr(hname);
@@ -181,32 +183,52 @@
    struct timeval tv;
    ssize_t len;
    FILE *fp;
+   int use_ssl = 0;
+   char **av;
+   int ac;
+   int n;
+   char *p;
+   SSL_METHOD *ssl_meth;
+   SSL_CTX* ctx;
+   SSL* ssl;

    port = 80;

-   if ((argc == 5) || (argc == 6)) {
-       if (argc == 5) {
-           host = argv[1];
-           port = atoi(argv[2]);
-           desthost = argv[3];
-           destport = argv[4];
+   ac = argc - 1;
+   av = argv + 1;
+   if (ac >= 1 && strcmp(av[0], "-ssl") == 0) {
+       use_ssl = 1;
+       av++;
+       ac--;
+       port = 443;
+   }
+   if (ac >= 4) {
+       host = av[0];
+       port = atoi(av[1]);
+       desthost = av[2];
+       destport = av[3];
+       av += 4;
+       ac -= 4;
+       if (ac > 1) {
+           usage();
+           exit(-1);
        }
-       if ((argc == 6)) {
-           host = argv[1];
-           port = atoi(argv[2]);
-           desthost = argv[3];
-           destport = argv[4];
-           fp = fopen(argv[5], "r");
+       if (ac == 1) {
+           fp = fopen(av[0], "r");
            if (fp == NULL) {
-               fprintf(stderr, "Error opening %s: %s\n", argv[5], strerror(errno));
+               fprintf(stderr, "Error opening %s: %s\n", av[0], strerror(errno));
                exit(-1);
-           } else {
-               char line[4096];
-               fscanf(fp, "%s", line);
-               up = malloc(sizeof(line));
-               up = line;
-               fclose(fp);
            }
+           if (fgets(buffer, sizeof buffer - 1, fp)) {
+               len = strlen(buffer);
+               if (buffer[len - 1] == '\n')
+                   buffer[len - 1] = '\0';
+               up = malloc(len + 1);
+               strcpy(up, buffer);
+           }
+           fclose(fp);
+           av++;
+           ac--;
        }
    } else {
        usage();
@@ -218,18 +240,40 @@
    strncat(uri, ":", sizeof(uri) - strlen(uri) - 1);
    strncat(uri, destport, sizeof(uri) - strlen(uri) - 1);
    strncat(uri, " HTTP/1.0", sizeof(uri) - strlen(uri) - 1);
-   if ((argc == 6) || (argc == 7)) {
-       strncat(uri, "\nProxy-Authorization: Basic ", sizeof(uri) - strlen(uri) - 1);
+   if (up && *up) {
+       strncat(uri, "\r\nProxy-Authorization: Basic ", sizeof(uri) - strlen(uri) - 1);
        strncat(uri, base64_encode(up), sizeof(uri) - strlen(uri) - 1);
    }
    strncat(uri, linefeed, sizeof(uri) - strlen(uri) - 1);

-   csock = sock_connect(host, port);
-   if(csock == -1) {
+   csock = socket(AF_INET, SOCK_STREAM, 0);
+   if (csock == -1) {
+       fprintf(stderr, "Couldn't create socket: %s\n", strerror(errno));
+       exit(-1);
+   }
+   if (sock_connect(csock, host, port) < 0 &&
+       errno && errno != EINPROGRESS) {
        fprintf(stderr, "Couldn't establish connection to proxy: %s\n", strerror(errno));
        exit(-1);
    }

+   if (use_ssl) {
+       SSLeay_add_ssl_algorithms();
+       SSL_load_error_strings();
+       SSL_library_init();
+       ssl_meth = SSLv23_client_method();
+       ctx = SSL_CTX_new(ssl_meth);
+       CHK_NULL(ctx);
+       SSL_CTX_set_options(ctx,SSL_OP_ALL);
+       ssl = SSL_new(ctx);
+       CHK_NULL(ssl);
+       SSL_set_fd(ssl, csock);
+       if (SSL_connect(ssl) < 0) {
+           fprintf(stderr, "Couldn't establish connection to proxy: %s\n", strerror(errno));
+           exit(-1);
+       }
+   }
+
    sent = 0;
    setup = 0;
    for(;;) {
@@ -249,7 +293,11 @@
        /* there's probably a better way to do this */
        if (setup == 0) {
            if (FD_ISSET(csock, &rfd)) {
-               len = read(csock, buffer, sizeof(buffer));
+               if (use_ssl) {
+                   len = SSL_read(ssl, buffer, sizeof(buffer));
+               } else {
+                   len = read(csock, buffer, sizeof(buffer));
+               }
                if (len<=0)
                    break;
                else {
@@ -265,7 +313,11 @@
                }
            }
            if (FD_ISSET(csock, &sfd) && (sent == 0)) {
-               len = write(csock, uri, strlen(uri));
+               if (use_ssl) {
+                   len = SSL_write(ssl, uri, strlen(uri));
+               } else {
+                   len = write(csock, uri, strlen(uri));
+               }
                if (len<=0)
                    break;
                else
@@ -273,7 +325,11 @@
            }
        } else {
            if (FD_ISSET(csock, &rfd)) {
-               len = read(csock, buffer, sizeof(buffer));
+               if (use_ssl) {
+                   len = SSL_read(ssl, buffer, sizeof(buffer));
+               } else {
+                   len = read(csock, buffer, sizeof(buffer));
+               }
                if (len<=0) break;
                len = write(1, buffer, len);
                if (len<=0) break;
@@ -282,10 +338,23 @@
            if (FD_ISSET(0, &rfd)) {
                len = read(0, buffer, sizeof(buffer));
                if (len<=0) break;
-               len = write(csock, buffer, len);
+               if (use_ssl) {
+                   len = SSL_write(ssl, buffer, len);
+               } else {
+                   len = write(csock, buffer, len);
+               }
                if (len<=0) break;
            }
        }
    }
+   if (use_ssl) {
+       SSL_shutdown(ssl);
+       close(csock);
+       SSL_free(ssl);
+       SSL_CTX_free(ctx);
+   } else {
+       close(csock);
+   }
+
    exit(0);
 }