// Return values typedef enum { PPHDRERR = -7, PPSENDERR, // failure to send to sock fd PPREADERR, // failure to read from sock fd PPINVALADDR, // invalid address PPINVALFAM, // invalid family value PPTRUNCATED, // truncated header PPINVALCMD, // invalid cmd PPNOERR = 0, // no error PPLOCALCMD, // local command in vercmd } pp_ret_t; // Version type typedef enum { PPROXY_V1 = 1, PPROXY_V2 } pproxy_ver_t; // Max length of a buffer for holding the PP header #define MAX_PP_LEN sizeof(pproxy_hdr_t) // Cast the sockaddr_in or sockaddr_in6 to sockaddr_storage #define SOCKADDR_STORAGE(addr) (struct sockaddr_storage *)addr

/* get_addr_family() : determine addr family and return  * I/P  * addr : sockaddr_storage address (IPv4/IPv6)  * O/P  * ret : AF_INET/AF_INET6, on error 0  */ uint8_t get_addr_family(struct sockaddr_storage *addr) /* proxy_ptc_v1_encode() : encode a proxy protocol header based  * on v1 specification  * I/P  * buf : buffer where encoded header will be  * placed  * len : total length of the header  * src : src address  * dst : dst address  *  * O/P  * return : 0 if success else errors in pp_ret_t  */ pp_ret_t proxy_ptc_v1_encode(char *buf, int8_t *len, struct sockaddr_storage *src, struct sockaddr_storage *dst) /* proxy_ptc_v2_encode() : encode a proxy protocol header based  * on v2 specification  * I/P   * buf : buffer where encoded header will be  * placed  * len : total length of the header  * src : src address  * dst : dst address  *  * O/P  * return : 0 if success else errors in pp_ret_t  */ pp_ret_t proxy_ptc_v2_encode(char *buf, int8_t *len, struct sockaddr_storage *src, struct sockaddr_storage *dst) /* proxy_ptc_send() : encode a proxy protocol header based  * on provided version and send into socket  * I/P  * fd : socket file descriptor  * ppver : protocol proxy version  * src : src address  * dst : dst address  *  * O/P  * return : 0 if success else errors in pp_ret_t  */ pp_ret_t proxy_ptc_send(int fd, pproxy_ver_t ppver, struct sockaddr_storage *src, struct sockaddr_storage *dst) /* proxy_ptc_decode() : decode a proxy protocol header from  * provided pkt buffer  * I/P   * buf : buffer where pkt has been received  * len : total length of the pkt  * ppver : ppver to set the version received  * src : src address to fill the src addr  * dst : dst address to fill the dest addr  *  * O/P  * return : total header size if success else   * errors in pp_ret_t  */ pp_ret_t proxy_ptc_decode(char *buf, int8_t len, pproxy_ver_t *ppver, struct sockaddr_storage *src, struct sockaddr_storage *dst) /* proxy_ptc_read() : read packet and decode a proxy protocol   * header from provided sock fd  * I/P   * fd : the file desc to read from  * ppver : ppver to set the version received  * src : src address to fill the src addr  * dst : dst address to fill the dest addr  *  * O/P  * return : 0 if success else errors in pp_ret_t  */ pp_ret_t proxy_ptc_read(int fd, pproxy_ver_t *ppver, struct sockaddr_storage *src, struct sockaddr_storage *dst)