https下载图片

OpenSSL用法示例

OpenSSL源码安装

对于ubuntu，懒得编译源码可以直接安装

sudo apt-get install libssl–dev

  /usr/include/openssl/ssl.h

CMakeLists中添加  

link_libraries(ssl crypto)

apt-get安装不需要再制定libssl.a, libcrypto.a的路径了, 就像用libc标准库一样。源码安装要指定-L/path/to/libssl.a或者-L/path/to/libssl.so , -lssl。客户端不需要生成证书。

sale.txt

GET /uploadfile/photo/20231022/37cac8bc693780b740b4e659846689cd.jpg HTTP/1.1
Accept: image/jpeg,image/avif,image/webp,image/apng,*/*
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7,ja;q=0.6
Connection: keep-alive
Host: img.sx2737.com
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36
 

* main.c

#include 
/* ... */
#include "https.h"
 
 
static int get_host_ip(char ip[], char hostname[]) {
    struct ipv4head ipv4List;
    struct ipv4_entry *n1;
    int count = 0;
    /* get ip by Gateway 10.0.0.1 */
    bcl_dns_query(&ipv4List, hostname, "10.0.0.1");
    while(!TAILQ_EMPTY(&ipv4List)) {
        n1 = TAILQ_FIRST(&ipv4List);
        TAILQ_REMOVE(&ipv4List, n1, entries);
        printf("ip=%s\n", n1->data);
        strncpy(ip, n1->data, 16);
        free(n1);
        count += 1;
    }
    return count;
}
 
int main(int argc, char *argv[]) {
    char path_dst[256];
    char path_src[256];
    char hostname[32] = {'\0'};
    char ip[16] = {'\0'};
    int sockfd = -1;
 
    bclerrinit();
 
    strcpy(path_src, "/mnt/e/CLionProjects/arp/fap30/input/sale.txt");
    strcpy(path_dst, "/mnt/e/CLionProjects/arp/fap30/print/sale.jpg");
 
    strcpy(hostname, "img.sx2737.com");  /* octipus.net, www.google.co.il */
    get_host_ip(ip, hostname);
 
    printf("path_dst=%s\n", path_dst);
    if (E_FAIL == https_get_body(ip,path_src, path_dst)) {
        bclerrlog(E_SOCKFD_RECV, _FL_, "https_get_body(%s,%s,%s)",ip,path_src,path_dst);
        return E_FAIL;
    }
    bclerrend();
    return E_OK;
}

网关直接固定写的10.0.0.1, 需要改。或者再实现一个拿到网关Gateway IP地址的函数 查DNS

DNS没做缓存，简化版测试查询DNS发UDP包。 一个域名对应多个ip，也不知道多少个ip，用的/usr/include/x86_64-linux-gnu/sys/queue.h  参照下面的bcl_udp.h

#include

* https.h

#ifndef ARP_TEST_HTTPS_H
#define ARP_TEST_HTTPS_H
 
#include  /* SSL_Library_init() */
#include 
 
int https_get_body(char *ip, char *in_path, char *out_path);
 
#endif //ARP_TEST_HTTPS_H

* https.c

/*
 * @ref: https://aticleworld.com/ssl-server-client-using-openssl-in-c/
 * sudo apt-get install libssl–dev
 * -L/path/to/ssl_dir -lssl -lcrypto
 */
#include  /* memset */
/* ... */
#include "https.h"
 
extern unsigned int ip2int(const char *ip);
 
static SSL_CTX *InitCTX(void) {
    SSL_METHOD *method;
    SSL_CTX *ctx;
    OpenSSL_add_all_algorithms();  /* Load cryptos, et.al. */
    SSL_load_error_strings();   /* Bring in and register error messages */
    method = TLSv1_2_client_method();  /* Create new client-method instance */
    ctx = SSL_CTX_new(method);   /* Create new context */
    if ( ctx == NULL ) {
        ERR_print_errors_fp(stderr);
        abort();
    }
    return ctx;
}
 
ssize_t send_from_file_ssl(SSL *ssl, char *path) {
    byte_t *buf = NULL;
    size_t isz = 0;
    ssize_t outBytes;
 
    buf = file_get_contents(path, &isz);
    outBytes = SSL_write(ssl, buf, isz);
    /* bcl_xxd(buf, isz); */
    free(buf);
    return outBytes;
}
 
int https_get_body(char *ip, char *in_path, char *out_path) {
    SSL_CTX *ctx = NULL;
    SSL *ssl;
    int bytes;
#define HTTPS_BUFF_SIZE 4096
    char buf[HTTPS_BUFF_SIZE];
    int sockfd = -1;
    FILE *out = NULL;
 
    SSL_library_init();
    ctx = InitCTX();
    ssl = SSL_new(ctx);      /* create new SSL connection state */
    sockfd = bcl_tcp_connector(ip2int(ip), 443);
    SSL_set_fd(ssl, sockfd);    /* attach the socket descriptor */
    if ( SSL_connect(ssl) < 0 ) {  /* perform the connection */
        ERR_print_errors_fp(stderr);
        return E_FAIL;
    }
    send_from_file_ssl(ssl, in_path);
    bytes = SSL_read(ssl, buf, HTTPS_BUFF_SIZE);
    /* Dump HTTP header */
    bcl_xxd(buf, bytes);
 
    out = fopen(out_path, "w");
    if (NULL == out) {
        bclerreg(E_OSCALL, _FL_, "fopen(%s)", out_path);
        return E_FAIL;
    }
    while (0<(bytes = SSL_read(ssl, buf, HTTPS_BUFF_SIZE))) {
        fwrite(buf, 1, bytes, out);
        memset(buf, 0, bytes);
    }
    fclose(out);
    bcl_closesock(sockfd);
 
    SSL_free(ssl);
    SSL_CTX_free(ctx);
    return E_OK;
}

先准备ssl需要的库, SSL_Libary_init(), 创建SSL_CTX *ctx对象   

封装socket fd为SSL *， 操作SSL *取代 int fd。SSL_read替换recv， SSL_write替换send

close(fd)关闭socket fd。用完SSL_free(ssl),  释放https链接。销毁SSL_CTX *ctx对象 

SSL_read第0次调用拿到http header，再调用得到的是http body。不需要手动解析http \r\n 0x0d 0x0a, 也省了很多麻烦。

int bcl_tcp_connector(u_int32_t _addr, u_int16_t _port) {
    struct sockaddr_in saddr;
    int sock;
    int ret;
 
    for (;;) {
        sock = socket(AF_INET, SOCK_STREAM, 0);
        if (sock <0) {
            /* ... */
            return E_FAIL;
        }
        memset(&saddr, 0x00, sizeof (saddr));
        saddr.sin_family = AF_INET;
        saddr.sin_addr.s_addr = _addr;
        saddr.sin_port = htons(_port);
 
        ret = connect(sock, (struct sockaddr *)&saddr, sizeof(saddr));
        if (ret >= 0) {
            return sock;
        }
        /* ERROR connect */
        if (errno == EINTR) {
            bcl_closesock(sock);
            continue;
        }
        char ip[16];
        bcl_int2ip(ip, _addr);
        bclerreg(E_OSCALL, _FL_, "Error connect %s:%d", ip, _port);
        return E_FAIL;
    }
}

创建socket fd，调用connect，常规方法。 

bcl_xxd函数hexdump调试用

uint8_t arc_xxd(byte *s, uint8_t len, void *param);
 
void bcl_xxd(const void *s, size_t len)
{
    uint16_t line = 0;
    byte *t = (byte *)s;
    uint8_t b;
    size_t left = len;
 
    for (; ;) {
        if (left > 16) {
            b = arc_xxd(t, 16, &line);
        } else {
            b = arc_xxd(t, left, &line);
        }
        if (b < 1) {break;}
        left -= b;
        if (left <= 0) {break;}
        t += b;
    }
}
 
uint8_t arc_xxd(byte *s, uint8_t len, void *param)
{
    uint8_t i;
    uint16_t *line = (uint16_t *)param;
    fprintf(stdout, "%08x:", *line << 4);
    for (i = 0; i+2 < len; i+=2) {
        fprintf(stdout, " %02x%02x", s[i], s[i+1]);
    }
    if (i fprintf(stdout, " %02x", s[i]); i+= 1;}
    if (i fprintf(stdout, "%02x", s[i]); i+=1;}
    if (i < 16 && 0x00 != (i & 0x01)) { fputs("  ", stdout); i+=1;}
    for (; i <16; i+= 2) {
        fputs("     ", stdout); /* space * 5 */
    }
    fputs("  ", stdout);
    for (i = 0; i 
        if (s[i] <0x20 || s[i] > 0x7e) {
            fputc('.', stdout);
        } else {
            fputc(s[i], stdout);
        }
    }
    fputs("\r\n", stdout);
    *line += 1;
    return i;
}

* bcl_udp.h

#ifndef ERRLOG_BCL_UDP_H
#define ERRLOG_BCL_UDP_H
 
#include 
 
typedef union {
    unsigned char c[4];
    unsigned int addr;
} IPv4_t;
 
void IPv4_toString(char *s, IPv4_t ipv4);
/* in_addr_t */ unsigned int ip2int(const char *ip);
 
 
struct ipv4_entry {
    char data[16];
    TAILQ_ENTRY(ipv4_entry) entries;
};
TAILQ_HEAD(ipv4head, ipv4_entry);
 
int bcl_dns_query(struct ipv4head *head, char *host_name, const char *dns_ip);
 
#endif //ERRLOG_BCL_UDP_H

* bcl_udp.c

#ifdef __cplusplus
extern "C" {
#endif
 
#include  /* bzero */
#include  /* inet_addr */
#include  /* close */
#include  /* strcat, memset */
#include  /* getenv(), rand() */
 
#include "bcl_udp.h"
#include "arclog.h"
#include "bcl_socket.h"
 
#define PRIVATE static
 
unsigned int /* in_addr_t */ip2int(const char *ip) {
    IPv4_t un;
    int i, j;
    un.c[0] = un.c[1] = un.c[2] = un.c[3] = 0;
    for (i = 0, j = 0; i < 16 && ip[i] != '\0'; i++) {
        if (0x30 <= ip[i] && ip[i] < 0x3a) { /* '0','9' */
            un.c[j] *= 10;
            un.c[j] += ip[i] - 0x30;
        } else if (ip[i] == 0x2e) { /* '.' */
            j += 1;
        }
    }
    return un.addr;
}
 
 
typedef struct {
    u_short transId; /* 0xb6f6 */
    u_short flags;  /* 0x0100 Standard query */
    u_short questions; /* 0x0001 */
    u_char rss[6];  /* 00 00 00 00 00 00 */
} DnsHdr_t;
 
#define HOST_LEN 64
 
typedef struct {
    u_char name[2]; /* ptr */
    u_short type; /* 0x0005 alias */
    u_short in; /* 0x0001 */
    u_int32_t ttl; /* 81, 1min21s */
    u_short dataLen;  /* 0x0017, 23 */
    char cname[HOST_LEN];  /* 3www31633com8163jiasu3com */
} __attribute__((packed)) DnsAnswer_t;
 
/**
 * @ref: https://www.linuxquestions.org/questions/linux-networking-3/dns-packet-structure-289886/
 * @param name "p3-sign.douyinpic.com"
 * @param entry  "7p3-sign9douyinpic3com"
 * @return
 */
PRIVATE char *dns_entry(char *entry, const char *name) {
    const char *p = name;
    char *q = entry;
    int8_t len;
 
    while ('\0' != *p) {
        len = 0;
        for (; *p && *p != '.'; p++) {
            len += 1;
        }
        *q++ = len;
        memcpy(q, p - len, len);
        q += len;
        p++;
    }
    return q;
}
 
#define SWAP(a, b, type) do { type _t = a; a = b; b = _t;} while(0);
 
#define REVERSE(a, b, type)  do { \
   type *p = a, *q = b;           \
   type t;                        \
   if (p > q) { SWAP(p, q, type *);}  \
   for (; p < q; p++, q--) { \
       t = *p; \
       *p = *q; \
       *q = t; \
   } \
} while (0);
 
void IPv4_toString(char *s, IPv4_t ipv4) {
    int i;
    char *t;
#ifdef __ORDER_LITTLE_ENDIAN__
    for (i = 0; i < 4; i++) {
#else
    for (i = 3; 0 <= i; i--) {
#endif
        t = s;
        while (ipv4.c[i]) {
            *s++ = ipv4.c[i] % 10 + 0x30;
            ipv4.c[i] /= 10;
        }
        REVERSE(s-1, t, char);
        *s++ = '.';
    }
    *(s-1) = '\0';
}
 
int bcl_dns_query(struct ipv4head *head, char *host_name, const char *dns_ip) {
    int sockfd;
    char buf[1024] = {'\0'};
    struct sockaddr_in dest_addr;
    DnsHdr_t header;
    char *p = NULL;
    off_t queryLen;
    DnsAnswer_t ans;
    IPv4_t ipv4;
    struct ipv4_entry *n1 = NULL;
 
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0) {
        bclerreg(E_OSCALL, _FL_, "socket() UDP");
        return E_FAIL;
    }
    /* DNS address */
    memset(&dest_addr, 0, sizeof(struct sockaddr_in));
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_addr.s_addr = ip2int(dns_ip);
    dest_addr.sin_port = htons(53);  /* DNS port 53 */
    if (connect(sockfd, (const struct sockaddr *) &dest_addr, sizeof(dest_addr)) < 0) {
        bclerreg(E_OSCALL, _FL_, "connect()");
        return E_FAIL;
    }
    /* DNS query packet */
    header.transId = (u_short) rand();
    header.flags = htons(0x0100);
    header.questions = htons(0x0001);
    memset(header.rss, 0, sizeof(header.rss));
 
    memcpy(buf, &header, sizeof(header));
    p = buf + sizeof(header);
    /* queries: p3-sign.douyinpic.com  */
    p = dns_entry(p, host_name);
    *p++ = '\0';
    /* type A, class IN */
    *p++ = 0x00; *p++ = 0x01;
    *p++ = 0x00; *p++ = 0x01;
 
    queryLen = p - buf;
    if (send(sockfd, buf, queryLen, 0) < 0) {
        bclerreg(E_OSCALL, _FL_, "send()");
        return E_FAIL;
    }
    memset(buf, 0, 1024);
    if (recv(sockfd, buf, 1024, 0) < 1) {
        bclerreg(E_OSCALL, _FL_, "recv()");
        return E_FAIL;
    }
    p = buf + queryLen;
    /* Answers: buf + queryLen */
    TAILQ_INIT(head);
    while (*p != 0x00) {
        /* bcl_xxd(p, 0xa0); */
        if (*(u_char *)p == 0xc0) {
            /* c0 0c, c0 14 */
            ans.dataLen = ntohs(((DnsAnswer_t *)p)->dataLen);
        }
#if DEBUG
        printf("dataLen=%d\n", ans.dataLen);
        bcl_xxd(((DnsAnswer_t *)p)->cname, ans.dataLen);
#endif
        if (4 == ans.dataLen) { /* IPv4 */
            memcpy(&ipv4, &((DnsAnswer_t *)p)->cname, 4);
            n1 = (struct ipv4_entry *)malloc(sizeof(struct ipv4_entry));
            IPv4_toString(n1->data, ipv4);
            TAILQ_INSERT_TAIL(head, n1, entries);
        }
        p += sizeof(DnsAnswer_t) - HOST_LEN + ans.dataLen;
    }
    return E_OK;
}
 
#ifdef __cplusplus
};
#endif

查询DNS以上

C:\Windows\system32\wsl.exe --distribution Ubuntu --exec /bin/bash -c "export ESWTDIR=/mnt/e/CLionProjects/arp && export FAPWORKDIR=/mnt/e/CLionProjects/arp/fap30 && cd /mnt/e/CLionProjects/arp/fap30 && /mnt/e/CLionProjects/arp/cmake-build-debug/arp_test ./input/banner.txt banner_3.jpg"
ip=61.164.142.245
ip=115.231.71.216
path_dst=/mnt/e/CLionProjects/arp/fap30/print/sale.jpg
00000000: 4854 5450 2f31 2e31 2032 3030 204f 4b0d  HTTP/1.1 200 OK.
00000010: 0a4c 6173 742d 4d6f 6469 6669 6564 3a20  .Last-Modified:
00000020: 5375 6e2c 2032 3220 4f63 7420 3230 3233  Sun, 22 Oct 2023
00000030: 2030 383a 3036 3a30 3320 474d 540d 0a45   08:06:03 GMT..E
00000040: 7461 673a 2022 3336 3333 3661 6665 3533  tag: "36336afe53
00000050: 3039 6561 3933 6163 6633 3930 6162 3934  09ea93acf390ab94
00000060: 3637 6132 6634 220d 0a43 6f6e 7465 6e74  67a2f4"..Content
00000070: 2d54 7970 653a 2069 6d61 6765 2f6a 7065  -Type: image/jpe
00000080: 670d 0a44 6174 653a 2053 756e 2c20 3232  g..Date: Sun, 22
00000090: 204f 6374 2032 3032 3320 3038 3a30 363a   Oct 2023 08:06:
000000a0: 3034 2047 4d54 0d0a 5365 7276 6572 3a20  04 GMT..Server:
000000b0: 7465 6e63 656e 742d 636f 730d 0a78 2d63  tencent-cos..x-c
000000c0: 6f73 2d68 6173 682d 6372 6336 3465 636d  os-hash-crc64ecm
000000d0: 613a 2031 3534 3631 3131 3537 3934 3831  a: 1546111579481
000000e0: 3535 3537 3339 340d 0a78 2d63 6f73 2d72  5557394..x-cos-r
000000f0: 6571 7565 7374 2d69 643a 204e 6a55 7a4e  equest-id: NjUzN
00000100: 4751 335a 574e 664e 5755 7a4e 6a51 774d  GQ3ZWNfNWUzNjQwM
00000110: 474a 664d 5745 305a 4446 664f 5459 314f  GJfMWE0ZDFfOTY1O
00000120: 4442 6b4e 673d 3d0d 0a43 6f6e 7465 6e74  DBkNg==..Content
00000130: 2d4c 656e 6774 683a 2032 3237 3938 0d0a  -Length: 22798..
00000140: 4163 6365 7074 2d52 616e 6765 733a 2062  Accept-Ranges: b
00000150: 7974 6573 0d0a 582d 4e57 532d 4c4f 472d  ytes..X-NWS-LOG-
00000160: 5555 4944 3a20 3735 3537 3138 3835 3632  UUID: 7557188562
00000170: 3130 3431 3837 3231 320d 0a43 6f6e 6e65  104187212..Conne
00000180: 6374 696f 6e3a 206b 6565 702d 616c 6976  ction: keep-aliv
00000190: 650d 0a58 2d43 6163 6865 2d4c 6f6f 6b75  e..X-Cache-Looku
000001a0: 703a 2043 6163 6865 2048 6974 0d0a 0d0a  p: Cache Hit....

Process finished with exit code 0

查看下载 E:\CLionProjects\arp\fap30\print\sale.jpg

对于http响应body，有的返回是gzip压缩，要用zlib库解压。分段的内容要解析

/** @ref: https://www.iteye.com/blog/dbscx-830644 */
char *http_chunked_parse(char *s, u_int16_t *len) {
    int i;
    /* 0x1000 == 4096 */
    *len = 0;
    for (i = 0; i < 4; i++) {
        if (s[i] == 0x0d && s[i+1] == 0x0a) {
            break;
        }
        /* 32 63 31 0d 0a <=> "3c1\r\n"(LEN=0x2c1, Dec:705) */
        *len *= 16;
        if (0x30<=s[i] && s[i] < 0x40) {
            *len += s[i] - 0x30;
        } else if (0x61 <= s[i] && s[i] < 0x67) {
            *len += s[i] - 0x61 + 10;
        }
    }
    if (s[i] == 0x0d && s[i+1] == 0x0a) {
        s = &s[i] + 2;
    }
    return s;
}

0d 0a 30 0d 0a 0d 0a 结束

SO2 Lab 10 - Networking