In this exercise, you have to create a IPv6 socket, set it to listening mode and read an incoming message. Then you have to perform some computation using the received message and send back the result to the message sender.
To create the socket, you have to use the socket() call and provide it with the correct parameters. Make sure to configure it for the IPv6 domain and set its type to support datagrams. Datagrams are simple messages abstractions.
Setting the socket to listen for incoming messages is achieved using the bind() call.
The recvfrom() call allows waiting for the receipt of a message, receiving this message and the associated sender address. A 1024-byte buffer should be sufficient to hold a message. Use a struct sockaddr_storage to receive the message sender address. For this exercice, recvfrom()'s flags argument will not be used.
The message you will receive is a sequence of numbers that are network-ordered integers. You have to sum all the numbers and send the result back to the message sender in network order. Use sendto() to send back the result.
For each of the calls that you use, if one of them were to encounter an error, immediately return -1. All C required headers are already included.
Manpages of interest: