Packet support

include/udpsocket.hpp

@@ -2,14 +2,22 @@
 #include <iostream>
 #include <stdexcept>
 #include <netdb.h>
-#include <stdlib.h>
+#include <string>
 #include <cstring>
+#include <cstdint>
 #include <sys/socket.h>
 #include <unistd.h>
 #include <netinet/in.h>
 #include <sys/types.h>
 #include <vector>
-
+struct packet{
+	struct sockaddr_in addr;
+	int m_port;
+	std::uint64_t checksum[4];
+	std::string content;
+	packet(const std::string& content, const std::string& dest, int port);
+	void setContent(const std::string&);
+};
 class udpsocket {
 	struct sockaddr_in addr;
 	int s, slen = sizeof(addr);

socket_impl/udpsocket_posix.cpp

@@ -1,4 +1,187 @@
-#include "udpsocket.hpp"
+#include <udpsocket.hpp>
+#include <cstdint>
+constexpr std::uint32_t sha256_k[64] = {0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
+             0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+             0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+             0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+             0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
+             0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+             0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
+             0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+             0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+             0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+             0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
+             0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+             0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
+             0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+             0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+             0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2};
+class SHA256{
+protected:
+    typedef unsigned char uint8;
+    typedef unsigned int uint32;
+    typedef unsigned long long uint64;
+    static const unsigned int SHA224_256_BLOCK_SIZE = (512/8);
+public:
+    void init();
+    void update(const unsigned char *message, unsigned int len);
+    void final(unsigned char *digest);
+    static const unsigned int DIGEST_SIZE = ( 256 / 8);
+ 
+protected:
+    void transform(const unsigned char *message, unsigned int block_nb);
+    unsigned int m_tot_len;
+    unsigned int m_len;
+    unsigned char m_block[2*SHA224_256_BLOCK_SIZE];
+    uint32 m_h[8];
+};
+#define SHA2_SHFR(x, n)    (x >> n)
+#define SHA2_ROTR(x, n)   ((x >> n) | (x << ((sizeof(x) << 3) - n)))
+#define SHA2_ROTL(x, n)   ((x << n) | (x >> ((sizeof(x) << 3) - n)))
+#define SHA2_CH(x, y, z)  ((x & y) ^ (~x & z))
+#define SHA2_MAJ(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
+#define SHA256_F1(x) (SHA2_ROTR(x,  2) ^ SHA2_ROTR(x, 13) ^ SHA2_ROTR(x, 22))
+#define SHA256_F2(x) (SHA2_ROTR(x,  6) ^ SHA2_ROTR(x, 11) ^ SHA2_ROTR(x, 25))
+#define SHA256_F3(x) (SHA2_ROTR(x,  7) ^ SHA2_ROTR(x, 18) ^ SHA2_SHFR(x,  3))
+#define SHA256_F4(x) (SHA2_ROTR(x, 17) ^ SHA2_ROTR(x, 19) ^ SHA2_SHFR(x, 10))
+#define SHA2_UNPACK32(x, str)                 \
+{                                             \
+    *((str) + 3) = (uint8) ((x)      );       \
+    *((str) + 2) = (uint8) ((x) >>  8);       \
+    *((str) + 1) = (uint8) ((x) >> 16);       \
+    *((str) + 0) = (uint8) ((x) >> 24);       \
+}
+#define SHA2_PACK32(str, x)                   \
+{                                             \
+    *(x) =   ((uint32) *((str) + 3)      )    \
+           | ((uint32) *((str) + 2) <<  8)    \
+           | ((uint32) *((str) + 1) << 16)    \
+           | ((uint32) *((str) + 0) << 24);   \
+}
+void sha256(std::uint64_t*, const std::string&);
+ 
+void SHA256::transform(const unsigned char *message, unsigned int block_nb){
+    uint32 w[64];
+    uint32 wv[8];
+    uint32 t1, t2;
+    const unsigned char *sub_block;
+    int i;
+    int j;
+    for (i = 0; i < (int) block_nb; i++) {
+        sub_block = message + (i << 6);
+        for (j = 0; j < 16; j++) {
+            SHA2_PACK32(&sub_block[j << 2], &w[j]);
+        }
+        for (j = 16; j < 64; j++) {
+            w[j] =  SHA256_F4(w[j -  2]) + w[j -  7] + SHA256_F3(w[j - 15]) + w[j - 16];
+        }
+        for (j = 0; j < 8; j++) {
+            wv[j] = m_h[j];
+        }
+        for (j = 0; j < 64; j++) {
+            t1 = wv[7] + SHA256_F2(wv[4]) + SHA2_CH(wv[4], wv[5], wv[6])
+                + sha256_k[j] + w[j];
+            t2 = SHA256_F1(wv[0]) + SHA2_MAJ(wv[0], wv[1], wv[2]);
+            wv[7] = wv[6];
+            wv[6] = wv[5];
+            wv[5] = wv[4];
+            wv[4] = wv[3] + t1;
+            wv[3] = wv[2];
+            wv[2] = wv[1];
+            wv[1] = wv[0];
+            wv[0] = t1 + t2;
+        }
+        for (j = 0; j < 8; j++) {
+            m_h[j] += wv[j];
+        }
+    }
+}
+ 
+void SHA256::init(){
+    m_h[0] = 0x6a09e667;
+    m_h[1] = 0xbb67ae85;
+    m_h[2] = 0x3c6ef372;
+    m_h[3] = 0xa54ff53a;
+    m_h[4] = 0x510e527f;
+    m_h[5] = 0x9b05688c;
+    m_h[6] = 0x1f83d9ab;
+    m_h[7] = 0x5be0cd19;
+    m_len = 0;
+    m_tot_len = 0;
+}
+ 
+void SHA256::update(const unsigned char *message, unsigned int len){
+    unsigned int block_nb;
+    unsigned int new_len, rem_len, tmp_len;
+    const unsigned char *shifted_message;
+    tmp_len = SHA224_256_BLOCK_SIZE - m_len;
+    rem_len = len < tmp_len ? len : tmp_len;
+    memcpy(&m_block[m_len], message, rem_len);
+    if (m_len + len < SHA224_256_BLOCK_SIZE) {
+        m_len += len;
+        return;
+    }
+    new_len = len - rem_len;
+    block_nb = new_len / SHA224_256_BLOCK_SIZE;
+    shifted_message = message + rem_len;
+    transform(m_block, 1);
+    transform(shifted_message, block_nb);
+    rem_len = new_len % SHA224_256_BLOCK_SIZE;
+    memcpy(m_block, &shifted_message[block_nb << 6], rem_len);
+    m_len = rem_len;
+    m_tot_len += (block_nb + 1) << 6;
+}
+ 
+void SHA256::final(unsigned char *digest){
+    unsigned int block_nb;
+    unsigned int pm_len;
+    unsigned int len_b;
+    int i;
+    block_nb = (1 + ((SHA224_256_BLOCK_SIZE - 9)
+                     < (m_len % SHA224_256_BLOCK_SIZE)));
+    len_b = (m_tot_len + m_len) << 3;
+    pm_len = block_nb << 6;
+    memset(m_block + m_len, 0, pm_len - m_len);
+    m_block[m_len] = 0x80;
+    SHA2_UNPACK32(len_b, m_block + pm_len - 4);
+    transform(m_block, block_nb);
+    for (i = 0 ; i < 8; i++) {
+        SHA2_UNPACK32(m_h[i], &digest[i << 2]);
+    }
+}
+ 
+void sha256(uint64_t* dest, const std::string& input){
+    unsigned char digest[SHA256::DIGEST_SIZE];
+    memset(digest,0,SHA256::DIGEST_SIZE);
+ 
+    SHA256 ctx = SHA256();
+    ctx.init();
+    ctx.update((const unsigned char*)input.c_str(), input.length());
+    ctx.final(digest);
+    unsigned char* cdest = (unsigned char*) dest;
+	memcpy(dest, digest, SHA256::DIGEST_SIZE);
+}
+
+packet::packet(const std::string& content, const std::string& dest, int port) : m_port(port){
+	hostent *server_host;
+	errno = 0;
+	server_host = gethostbyname(dest.c_str());
+	if(errno){
+		throw std::logic_error("Could not resolve hostname " + dest + ": " + strerror(errno));
+	}
+	/* configure the server address */
+	struct sockaddr_in server_addr;
+	server_addr.sin_family = AF_INET; // IPv4
+	memcpy(&server_addr.sin_addr, server_host->h_addr,
+			sizeof(struct in_addr)); server_addr.sin_port = htons(port);
+	this->content = content;
+	sha256(checksum, this->content);
+}
+void packet::setContent(const std::string& content){
+	this->content = content;
+	sha256(checksum, this->content);
+}
+
 udpsocket::udpsocket(int port) : m_port(port){
 	if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
 		throw std::logic_error(std::string("Socket creation failed: ") + strerror(errno));