IPv6

Intro & Demo

Yuxin OuyangYuhui Feng

Why IPv6

• Space allowed by IPv4 is saturating

• IPv4 is not secure by itself

• Data prioritization in IPv4 is not up to date

• Does not provide a mechanism to have a globally unique IP address

Features

• Larger address space

• Simplified Header

• End-to-end Connectivity

• and more…

IPv6 - Addressing Modes

• Unicast

• Multicast

• And…Anycast

IPv6 - Anycast

• When a host wishes to communicate with a host equipped with an Anycast IP address, it sends a Unicast message. With the help of complex routing mechanism, that Unicast message is delivered to the host closest to the Sender in terms of Routing cost.

IPv6 - Anycast

IPv6 Subnetting

• The second half of the address (least significant 64 bits) is always used for hosts only. Therefore, there is no compromise if we sub-net the network.

• /48 prefix can be allocated to an organization providing it the ben-efit of ha-ving up to /64 subnet prefixes

• 16 bits of subnet is equivalent to IPv4’s Class B Network. Using these sub-net bits, an organization can have another 65 thou-sands of subnets which is by far, more than enough.

IPv6 Subnetting

IPv6 - Header• Version (4-bits)

• Traffic Class (8-bits)

• Flow Label (20-bits)

• Payload Length (16-bits)

• Next Header (8-bits)

• Hop Limit (8-bits)

• Source Address (128-bits)

• Destination Address (128-bits)

IPv6 – Mobility(connected to home link)

IPv6 – Mobility(connected to foreign link)

include <netinet/in.h>struct sockaddr_in6 {

u_int16_t sin6_family; // address family, AF_INET6

u_int16_t sin6_port; // port number, Network Byte Order

u_int32_t sin6_flowinfo; // IPv6 flow informationstruct in6_addr sin6_addr; // IPv6 addressu_int32_t sin6_scope_id; // Scope ID

};

struct in6_addr {unsigned char s6_addr[16]; // load with inet_pton()

};

IPv6 socket programming

// General socket address holding structure, big enough to hold either// struct sockaddr_in or struct sockaddr_in6 data:

struct sockaddr_storage {sa_family_t ss_family; // address familychar __ss_pad1[_SS_PAD1SIZE];int64_t __ss_align;char __ss_pad2[_SS_PAD2SIZE];

};

IPv6 socket programming

IPv6 socket programming

IPv4 IPv6

Family AF_INET AF_INET6

IP address Structure sockaddr_in sockaddr_in6

Wildcard address INADDR_ANY in6addr_any

string->IP address inet_aton( ) inet_pton( )

IP address-> string inet_ntoa( ) inet_ntop( )

Get IP address by host name gethostbyname( ) getaddrinfo( )

Get host name by IP address gethostbyaddr( ) getnameinfo( )

int main(int argc, const char * argv[]) { unsigned int client_s; //Connection socket descriptor struct sockaddr_in6 server_addr; //Server Internet address char out_buf[BUFSIZE]; //Output buffer char in_buf[BUFSIZE]; //Input buffer const char *ip_num="::1"; const char *port_num="10501"; const char *file_name="1.jpg"; int port=atoi(port_num); server_addr.sin6_family =AF_INET6; server_addr.sin6_port =htons(port); inet_pton(AF_INET6, ip_num, &server_addr.sin6_addr); //Socket client_s=socket(AF_INET6,SOCK_STREAM,0); //Connection connect(client_s,(struct sockaddr *)&server_addr,sizeof(server_addr)); //Start file and find the size of it FILE *fp=fopen(file_name,"r"); //Send the file name to server bzero(out_buf,BUFSIZE); strncpy(out_buf,file_name,strlen(file_name)); send(client_s,out_buf,(strlen(out_buf)+1),0); //Start to transfer the file data long int send_length=0; bzero(out_buf,BUFSIZE); while ((send_length=fread(out_buf,sizeof(char),BUFSIZE,fp))>0){ if (send(client_s,out_buf,send_length,0)<0){ perror("File send failed."); exit(1); } bzero(out_buf,BUFSIZE); } fclose(fp); close(client_s); return 0;}

Client TCP

int main(int argc, const char * argv[]) { unsigned int server_s; //Server socket descriptor and bind indicator struct sockaddr_in6 server_addr, client_addr; //Server and Client internet address unsigned int connect_s; //Connection socket descriptor unsigned int addr_len; //Internet address length char out_buf[BUFSIZE]; //Output buffer for data char in_buf[BUFSIZE]; //Input buffer for data char file_name[FILENAME_SIZE+1]; //File name for transferred onst char *port_num="10501"; long int port =atoi(port_num); server_addr.sin6_family =AF_INET6; server_addr.sin6_port =htons(port); server_addr.sin6_addr =in6addr_any; //Socket server_s=socket(AF_INET6,SOCK_STREAM,0); //Bind bind(server_s,(struct sockaddr *)&server_addr,sizeof(server_addr)); //Listen listen(server_s,SERVER_QUEUE); //Accept conncection addr_len=sizeof(client_addr); connect_s=accept(server_s,(struct sockaddr *)&client_addr,&addr_len); //Receive the file name from client bzero(in_buf,BUFSIZE); bzero(file_name,FILENAME_SIZE+1); recv(connect_s,in_buf,sizeof(in_buf),0); strncpy(file_name,in_buf,FILENAME_SIZE); //Create a file to write the data; FILE *fp=fopen(file_name,"w");

Server TCP

//Receive data from client to buffer and write them into the file long int recv_length; bzero(in_buf,BUFSIZE); while ((recv_length=recv(connect_s,in_buf,sizeof(in_buf),0))>0){ if(fwrite(in_buf,sizeof(char),recv_length,fp)<recv_length){ perror("File write filed.\n"); exit(1); } bzero(in_buf,BUFSIZE); } char str[40]; //IPv6 address in string inet_ntop(AF_INET6, &(client_addr.sin6_addr), str, 40); printf("File '%s' recieved successful!(From IP= '%s' port ='%d')\n", file_name, str, ntohs(client_addr.sin6_port)); fclose(fp); close(connect_s); close(server_s); return 0;}

http://www.tutorialspoint.com/ipv6/index.htm Tutorialspoint

http://en.wikipedia.org/wiki/IPv6 Wikipedia IPv6

http://beej.us/guide/bgnet/output/html/multipage/sockaddr_inman.html Beej's Guide to Network Programming

Reference