揭开unix网络之纱8ioctl获得网络接口.doc

第 PAGE 9 页 共 3 页 揭开unix网络之纱8- ioctl获得网络接口 概述 需处理网络接口的许多程序沿用的初始步骤之一就是从内核获取配置在系统中的所有接口。本任务由SIOCGIFCONF请求完成，它使用ifconf结构，ifconf又使用ifreq结构。 Ifconfig结构 net/if.h struct ifconf{ int ifc_len; union{ caddr_t ifcu_buf; struct ifreq* ifcu_req; }ifc_ifcu; }; #define ifc_buf ifc_ifcu.ifcu_buf #define ifc_req ifc_ifcu.ifcu_req #define IFNAMSIZ 16 Struct ifreq{ Char ifr_name[IFNAMSIZ]; Union{ Struct sockaddr ifru_addr; Struct sockaddr ifru_dstaddr; Struct sockaddr ifru_broadaddr; Short ifru_flags; Int ifru_metric; Caddr_t ifru_data; }ifr_ifru; }; #define ifr_addr ifr_ifru.ifru_addr #define ifr_dstaddr ifr_ifru.ifru_dstaddr #define ifr_broadaddr ifr_ifru.ifru_broadaddr #define ifr_flags ifr_ifru.ifru_flags #define ifr_metric ifr_ifru.ifru_metric #define ifr_data ifr_ifru.ifru_data Unp_ifi.h #ifndef __UNP_IFI_H #define __UNP_IFI_H #include net/if.h #define IFI_NAME 16 /*same as IFNAMSIZ in net/if.*/ #define IFI_HADDR 8 /*allow for 64-bit EUI-64 in future*/ struct ifi_info{ char ifi_name[IFI_NAME]; /*interface name,null-terminated*/ short ifi_index; /*interface index*/ short ifi_mtu; /*interface MTU*/ u_char ifi_haddr[IFI_HADDR]; /*hardware address*/ u_short ifi_hlen; /*#bytes in hardware address: 0,6,8*/ short ifi_flags; /*IFF_XXX constants from net/if.h*/ short ifi_myflags; /*our own IFI_XXX flags*/ struct sockaddr *ifi_addr; /*primary address*/ struct sockaddr *ifi_brdaddr; /*broadcast address*/ struct sockaddr *ifi_dstaddr; /*destination address*/ struct ifi_info *ifi_next; /*next of these structures*/ }; #define IFI_ALIAS 1 /*ifi_addr is an alias*/ /*function prototypes*/ struct ifi_info *get_ifi_info(int,int); void free_ifi_info(struct ifi_info *); #endif get_ifi_info #include unistd.h #include sys/socket.h #include sys/types.h #include errno.h #include netinet/in.h #include sys/ioctl.h #include