networking learning

7 files changed, 276 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..af9fd70
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,36 @@
+CC=egcc
+CFLAGS_TESTBIN=-O3 -Wfatal-errors -Wall -Werror -Wextra -g -Wpedantic -std=gnu99
+CFLAGS=-O3 -flto -march=native -DNDEBUG -fomit-frame-pointer -s -std=gnu99
+MAKEFLAGS += -j$(nproc)
+TARGETS=helloworld
+TARGETS2=binding
+TARGETS3=listen
+TARGETS4=connecting
+TARGETS5=
+TESTTARGET=helloworld-t
+TESTTARGET2=binding-t
+TESTTARGET3=listen-t
+TESTTARGET4=connecting-t
+TESTTARGET5=
+SRCS=hello.c
+SRCS2=binding.c
+SRCS3=listen.c
+SRCS4=connecting.c
+SRCS5=
+
+all: release
+clean:
+	rm -f bin/$(TARGETS) bin/$(TARGETS2) bin/$(TARGETS3) bin/$(TARGETS4)
+	rm -f test/$(TESTTARGET) test/$(TESTTARGET2) test/$(TESTTARGET3) test/$(TESTTARGET4)
+
+tests:
+	$(CC) $(CFLAGS_TESTBIN) $(SRCS) -o test/$(TESTTARGET)
+	$(CC) $(CFLAGS_TESTBIN) $(SRCS2) -o test/$(TESTTARGET2)
+	$(CC) $(CFLAGS_TESTBIN) $(SRCS3) -o test/$(TESTTARGET3)
+	$(CC) $(CFLAGS_TESTBIN) $(SRCS4) -o test/$(TESTTARGET4)
+
+release:
+	$(CC) $(CFLAGS) $(SRCS) -o bin/$(TARGETS)
+	$(CC) $(CFLAGS) $(SRCS2) -o bin/$(TARGETS2)
+	$(CC) $(CFLAGS) $(SRCS3) -o bin/$(TARGETS3)
+	$(CC) $(CFLAGS) $(SRCS4) -o bin/$(TARGETS4)
diff --git a/README b/README
new file mode 100644
index 0000000..0eb1121
--- /dev/null
+++ b/README
@@ -0,0 +1 @@
+Im trying to learn networking
diff --git a/binding.c b/binding.c
new file mode 100644
index 0000000..ebc503d
--- /dev/null
+++ b/binding.c
@@ -0,0 +1,45 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+#define _FAIL_EXIT -1
+
+// Bind section of beej networking
+
+int main () {
+
+    struct addrinfo hints;
+    struct addrinfo *res;
+    int sockfd;
+    int status;
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = AF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = AI_PASSIVE;
+    status = getaddrinfo(NULL, "61000", &hints, &res);
+    if(status != 0) {
+        fprintf(stderr, "Error: %s\n", gai_strerror(status));
+        exit(_FAIL_EXIT);
+    } 
+
+    sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
+    if (sockfd == -1) {
+        exit(_FAIL_EXIT);
+    }
+
+    int bstatus;
+    bstatus = bind(sockfd, res->ai_addr, res->ai_addrlen);
+
+    fprintf(stdout, "%d\n", bstatus);
+    return 0;
+
+}
diff --git a/connecting.c b/connecting.c
new file mode 100644
index 0000000..fe9b99e
--- /dev/null
+++ b/connecting.c
@@ -0,0 +1,36 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+int main () {
+
+	int sockfd;
+    struct addrinfo *res;
+    struct addrinfo hints;
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_INET;
+	hints.ai_socktype = SOCK_STREAM;
+	int result = getaddrinfo("192.168.1.18", "62000", &hints, &res);
+	if (result != 0) {
+		exit(0);
+	}
+
+	sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
+	int connect_res = connect(sockfd, res->ai_addr, res->ai_addrlen);
+	if (connect_res == -1) {
+		fprintf(stderr, "connect_res: -1\n");
+		exit(1);
+	}
+	
+	
+    return 0;  
+}
diff --git a/hello.c b/hello.c
new file mode 100644
index 0000000..fbe02a3
--- /dev/null
+++ b/hello.c
@@ -0,0 +1,69 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+// BEEJ NETWORKING 5.1
+
+int main (int argc, char *argv[]) {
+
+    if (argc > 2 || argc == 1) {
+        fprintf(stderr, "Too many or not enough arguments! \n");
+        fprintf(stderr, "USAGE: getip [DOMAIN]\n");
+        exit(1);
+    }
+    char ipstr[INET_ADDRSTRLEN]; // We store the IP address in text form here. INET_ADDRSTRLEN is the length of ipv4 addresses.
+    int status;
+	struct addrinfo hints; // Struct where we put information in to pass it to getaddrinfo.
+    struct addrinfo *res; // The result of getaddrinfo. Not sure why its a pointer but ill figure that out later
+    struct addrinfo *rescpy; // Another rescpy struct pointer. This one is used to point to the next element when iterating in a for loop.
+    memset(&hints, 0, sizeof hints); // Set all values to 0 in hints.
+    hints.ai_family = AF_INET; // Add the necessary info to ai_family, ai_socktype, ai_flags.
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = AI_PASSIVE;
+    
+    status = getaddrinfo(argv[1], "62222", &hints, &res); // get addrinfo. Address to hints and res passed.
+    if (status != 0) {
+        fprintf(stderr, "Error: %s\n", gai_strerror(status));
+        exit(1);
+    }
+
+    // rescpy = res. Both point to the same result.
+    // rescpy != NULL. If its NULL then the next struct in the linked list is the last one.
+    // rescpy = rescpy->ai_next. After it did the loop it goes back, checks if its null. If not then rescpy is assigned the pointer to ai_next. And so on and so on.
+    // A visual representation:
+    // 
+    // res --> GAI_RESULT_STRUCT (res points to the result addrinfo struct)
+    // rescpy = res (BOTH POINT TO GAI_RESULT_STRUCT)
+    // IF rescpy is not NULL 
+    // 
+    // rescpy = rescpy --> ai_next (Its easier for me to imagine this line with some different syntax: rescpy = rescpy.ai_next. This is technically not correct but this is for my eyes only.)
+    // ai_next is a pointer to another addrinfo struct. Which is the next item in the linked list. rescpy = rescpy --> ai_next, this basically means we access the ai_next member
+    // which is inside GAI_RESULT_STRUCT. We basically make rescpy point to the next item.
+    //
+    //
+
+    for(rescpy = res ; rescpy != NULL ; rescpy = rescpy->ai_next) {
+        struct sockaddr_in *sa1 = (struct sockaddr_in *)rescpy->ai_addr; // struct sockaddr_in sa1 pointer assigned ai_addr. sa1 now points to ai_addr.
+                                                                     // ai_addr may be a sockaddr_in or a sockaddr_in6.
+                                                                     // We cast it to sockaddr_in which is supposed to just work. 
+        void *addr = &(sa1->sin_addr); // Address of sin_addr. sa1 now points to ai_addr so we access the item sin_addr and make addr point to it.
+        inet_ntop(rescpy->ai_family, addr, ipstr, rescpy->ai_addrlen);
+
+        fprintf(stdout, "%s\n", ipstr);
+
+    }
+
+    freeaddrinfo(res);
+    
+    return 0;
+
+}
diff --git a/listen.c b/listen.c
new file mode 100644
index 0000000..8557a60
--- /dev/null
+++ b/listen.c
@@ -0,0 +1,83 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+// int listen(int sockfd, int backlog); 
+
+#define BACKLOG 2
+
+int main () {
+
+	int sockfd;
+	int gai_result;
+	int bind_result;
+	struct addrinfo *res;
+	struct addrinfo hints;
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_INET;
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_flags = AI_PASSIVE;
+
+	gai_result = getaddrinfo(NULL, "62000", &hints, &res);
+	if (gai_result != 0) {
+		fprintf(stderr, "gai_result: %d\n", gai_result);
+		exit(1);
+	}
+
+	sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
+	if (sockfd == -1) {
+		fprintf(stderr, "sockfd: %d\n", sockfd);
+		exit(1);
+	}
+
+	bind_result = bind(sockfd, res->ai_addr, res->ai_addrlen);
+	if (bind_result != 0) {
+		fprintf(stderr, "bind_result: %d\n", bind_result);
+		exit(1);
+	}
+
+	listen(sockfd, BACKLOG);
+	socklen_t addr_size;
+	struct sockaddr_storage their_addr;
+	addr_size = sizeof(their_addr);
+	int newfd;
+	newfd = accept(sockfd, (struct sockaddr *)&their_addr, &addr_size);
+	if (newfd == -1) {
+		fprintf(stderr, "newfd: %d\n", newfd);
+		exit(1);
+	}
+
+	char *msg = "Server says hi!\n";
+	int len;
+	int bytes_sent;
+	len = strlen(msg);
+	bytes_sent = send(newfd, msg, len, 0);
+
+	int rlen = 1000;
+	int recv_ret;
+	size_t bytes_recieved = 0;
+	while(true) {
+
+		char recvmsg[rlen]; 
+		recv_ret = recv(newfd, recvmsg, rlen, 0);
+		bytes_recieved = bytes_recieved+recv_ret;
+		if (recv_ret < 1) {
+			break;
+		}
+		recvmsg[recv_ret] = '\0';
+		fprintf(stdout, "%s", recvmsg);
+		memset(&recvmsg, 0, (size_t)rlen);
+	}
+	fprintf(stdout, "bytes recieved: %ld\nbytes sent: %d\n", bytes_recieved, bytes_sent);
+ 
+	return 0;
+}
diff --git a/test/Makefile b/test/Makefile
new file mode 100644
index 0000000..48a5814
--- /dev/null
+++ b/test/Makefile
@@ -0,0 +1,6 @@
+all: release
+clean:
+	cd .. && make clean
+
+release:
+	cd .. && make tests