. .

|\/\/|

|____|

.-----------. .-----------. .------. .-----.

/ \.-------./ \.-------*-. | | |----------.

| | .--. \ | / '-' | \

'---. .---' '--' |-. .-:-' /____/_ | .-. |www.c-asm.com

| | .---.___-' | | '.____ \ | | | |www.x.com/7etsuo

| | '-___-''\ | | / | / '-' |discord.gg/c-asm

| |\ \ | |/ |-_______-' /

'-_____-' '--_______--' '-_____-'-.__________.' '-__________.'

2024 Shoutout to DeLuks

▗▖ ▗▄▄▄▖▗▖ ▗▖▗▖ ▗▖▗▖ ▗▖ ▗▄▄▖ ▗▄▖ ▗▄▄▖▗▖ ▗▖▗▄▄▄▖▗▄▄▄▖ for the Tetsuo graphics

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1. Interaction

2. Port and Service Functions

TCP Server getservbyname(char *name, char *proto) // Fetch port by service name and protocol

┌───────────────────┐ getservbyport(int port, char *proto) // Fetch service name by port and protocol

│ socket() │

└─────────┬─────────┘ 3. Byte Ordering Functions

│ htons (unsigned short hostshort) // Convert 16-bit host to network byte order

┌─────────▼─────────┐ htonl (unsigned long hostlong) // Convert 32-bit host to network byte order

known port │ bind() │ ntohs (unsigned short netshort) // Convert 16-bit network to host byte order

└─────────┬─────────┘ ntohl (unsigned long netlong) // Convert 32-bit network to host byte order

│

┌─────────▼─────────┐ 4. IP Address Functions

│ listen() │ inet_aton (const char *strptr, s ruct in_addr *addrptr) // Convert string to network address

└─────────┬─────────┘ inet_addr (const char *strptr) // Convert string to IPv4 address (32-bit network order)

│ inet_ntoa (struct in_addr inaddr) // Convert IPv4 address to string

┌─────────▼─────────┐

│ accept() │ 5. Socket Core Functions

└─────────┬─────────┘ socket (int family, int type, int protocol) // Get socket descriptor

│ connect (int sockfd, struct sockaddr *serv_addr, int addrlen) // Connect to server

TCP Client ▼ bind (int sockfd, struct sockaddr *my_addr, int addrlen) // Bind socket to local address

┌───────────────────┐ blocks until connection listen (int sockfd, int backlog) // Listen for incoming connections

│ socket() │ from client accept (int sockfd, struct sockaddr *cliaddr, socklen_t *addrlen) // Accept connection

└─────────┬─────────┘ │ send (int sockfd, const void *msg, int len, int flags) // Send data

│ │ recv (int sockfd, void *buf, int len, unsigned int flags) // Receive data

┌─────────▼─────────┐ connection │ sendto (int sockfd, const void *msg, int len, unsigned int flags, const struct sockaddr *to, int tolen) // Send to UNCONNECTED socket

│ connect() ◄─────────────────────► recvfrom (int sockfd, void *buf, int len, unsigned int flags, struct sockaddr *from, int *fromlen) // Receive from UNCONNECTED socket

└─────────┬─────────┘(TCP 3-way handshake)│ close (int sockfd) // Close socket

│ │ shutdown (int sockfd, int how) // Gracefully close socket

┌─────────▼─────────┐ │ select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *timeout) // Monitor multiple sockets

┌─────► write() ┼────┐ ┌─────────▼─────────┐

│ └─────────┬─────────┘ └──────► read() │ 6. Socket Helper Functions

│ │ └─────────┬─────────┘ write (int fildes, const void *buf, int nbyte) // Write to file descriptor

│ │ │ read (int fildes, const void *buf, int nbyte) // Read from file descriptor

│ │ ▼ fork (void) // Create new process

│ │ process request bzero (void *s, int nbyte) // Set memory to 0

│ │ │ bcmp (const void *s1, const void *s2, int nbyte) // Compare byte strings

│ │ │ bcopy (const void *s1, void *s2, int nbyte) // Copy byte strings

│ │ ┌─────────▼─────────┐ memset (void *s, int c, int nbyte) // Set memory to specific value

│ │ ┌──────┼ write() │

│ ┌──────────▼────────┐ data(reply)└─────────┬─────────┘ 7. Linux Socket Structures

└────│ read() ◄─────┘ │ sockaddr

└──────────┬────────┘ │ struct sockaddr { unsigned short sa_family; char sa_data[14]; } // Generic socket address

│ ┌─────────▼─────────┐ sockaddr_in

│ │ read() │ struct sockaddr_in { short int sin_family; unsigned short int sin_port; struct in_addr sin_addr; unsigned char sin_zero[8]; } // IPv4 address

│ └─────────┬─────────┘ in_addr

┌──────────▼────────┐ │ struct in_addr { unsigned long s_addr; } // 32-bit IPv4 address

│ close() ├────┐ │ hostent

└───────────────────┘ EOF ┌─────────▼─────────┐ struct hostent { char *h_name; char **h_aliases; int h_addrtype; int h_length; char **h_addr_list; } // Host information

└───────► close() │ servent

└───────────────────┘ struct servent { char *s_name; char **s_aliases; int s_port; char *s_proto; } // Service and port information