/* * The DEVICE structure. * Actually, this whole structure is a big mistake. It mixes I/O * data with strictly "high-level" data, and it has to know about * almost every data structure used in the INET module. * * FIXME: cleanup struct net_device such that network protocol info * moves out. */ struct net_device { /* * This is the first field of the "visible" part of this structure * (i.e. as seen by users in the "Space.c" file). It is the name * of the interface. */ char name[IFNAMSIZ]; //网络设备的具体名字 struct pm_qos_request_list pm_qos_req; /* device name hash chain */ struct hlist_node name_hlist; /* snmp alias */ char *ifalias; /* * I/O specific fields * FIXME: Merge these and struct ifmap into one */ unsigned long mem_end; /* shared mem end */ //设备说是用的共享内存的起始和结束地址 unsigned long mem_start; /* shared mem start */ unsigned long base_addr; /* device I/O address */ //网络设备I/O基地址 unsigned int irq; /* device IRQ number */ //设备使用的中断号 /* * Some hardware also needs these fields, but they are not * part of the usual set specified in Space.c. */ unsigned char if_port; /* Selectable AUI, TP,..*/ //指定多端口设备使用哪个端口，仅针对多端口设备 unsigned char dma; /* DMA channel */ //分配给该设备的 DMA 通道 unsigned long state; struct list_head dev_list; struct list_head napi_list; struct list_head unreg_list; /* Net device features */ unsigned long features; #define NETIF_F_SG 1 /* Scatter/gather IO. */ #define NETIF_F_IP_CSUM 2 /* Can checksum TCP/UDP over IPv4. */ #define NETIF_F_NO_CSUM 4 /* Does not require checksum. F.e. loopack. */ #define NETIF_F_HW_CSUM 8 /* Can checksum all the packets. */ #define NETIF_F_IPV6_CSUM 16 /* Can checksum TCP/UDP over IPV6 */ #define NETIF_F_HIGHDMA 32 /* Can DMA to high memory. */ #define NETIF_F_FRAGLIST 64 /* Scatter/gather IO. */ #define NETIF_F_HW_VLAN_TX 128 /* Transmit VLAN hw acceleration */ #define NETIF_F_HW_VLAN_RX 256 /* Receive VLAN hw acceleration */ #define NETIF_F_HW_VLAN_FILTER 512 /* Receive filtering on VLAN */ #define NETIF_F_VLAN_CHALLENGED 1024 /* Device cannot handle VLAN packets */ #define NETIF_F_GSO 2048 /* Enable software GSO. */ #define NETIF_F_LLTX 4096 /* LockLess TX - deprecated. Please */ /* do not use LLTX in new drivers */ #define NETIF_F_NETNS_LOCAL 8192 /* Does not change network namespaces */ #define NETIF_F_GRO 16384 /* Generic receive offload */ #define NETIF_F_LRO 32768 /* large receive offload */ /* the GSO_MASK reserves bits 16 through 23 */ #define NETIF_F_FCOE_CRC (1 << 24) /* FCoE CRC32 */ #define NETIF_F_SCTP_CSUM (1 << 25) /* SCTP checksum offload */ #define NETIF_F_FCOE_MTU (1 << 26) /* Supports max FCoE MTU, 2158 bytes*/ #define NETIF_F_NTUPLE (1 << 27) /* N-tuple filters supported */ #define NETIF_F_RXHASH (1 << 28) /* Receive hashing offload */ /* Segmentation offload features */ #define NETIF_F_GSO_SHIFT 16 #define NETIF_F_GSO_MASK 0x00ff0000 #define NETIF_F_TSO (SKB_GSO_TCPV4 << NETIF_F_GSO_SHIFT) #define NETIF_F_UFO (SKB_GSO_UDP << NETIF_F_GSO_SHIFT) #define NETIF_F_GSO_ROBUST (SKB_GSO_DODGY << NETIF_F_GSO_SHIFT) #define NETIF_F_TSO_ECN (SKB_GSO_TCP_ECN << NETIF_F_GSO_SHIFT) #define NETIF_F_TSO6 (SKB_GSO_TCPV6 << NETIF_F_GSO_SHIFT) #define NETIF_F_FSO (SKB_GSO_FCOE << NETIF_F_GSO_SHIFT) /* List of features with software fallbacks. */ #define NETIF_F_GSO_SOFTWARE (NETIF_F_TSO | NETIF_F_TSO_ECN | NETIF_F_TSO6 | NETIF_F_UFO) #define NETIF_F_GEN_CSUM (NETIF_F_NO_CSUM | NETIF_F_HW_CSUM) #define NETIF_F_V4_CSUM (NETIF_F_GEN_CSUM | NETIF_F_IP_CSUM) #define NETIF_F_V6_CSUM (NETIF_F_GEN_CSUM | NETIF_F_IPV6_CSUM) #define NETIF_F_ALL_CSUM (NETIF_F_V4_CSUM | NETIF_F_V6_CSUM) /* * If one device supports one of these features, then enable them * for all in netdev_increment_features. */ #define NETIF_F_ONE_FOR_ALL (NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ROBUST | NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_FRAGLIST) /* Interface index. Unique device identifier */ int ifindex; int iflink; struct net_device_stats stats; atomic_long_t rx_dropped; /* dropped packets by core network * Do not use this in drivers. */ #ifdef CONFIG_WIRELESS_EXT /* List of functions to handle Wireless Extensions (instead of ioctl). * See <net/iw_handler.h> for details. Jean II */ const struct iw_handler_def * wireless_handlers; /* Instance data managed by the core of Wireless Extensions. */ struct iw_public_data * wireless_data; #endif /* Management operations */ const struct net_device_ops *netdev_ops; const struct ethtool_ops *ethtool_ops; /* Hardware header description */ const struct header_ops *header_ops; unsigned int flags; /* interface flags (a la BSD) */ //网络接口标志 unsigned short gflags; unsigned int priv_flags; /* Like 'flags' but invisible to userspace. */ unsigned short padded; /* How much padding added by alloc_netdev() */ unsigned char operstate; /* RFC2863 operstate */ unsigned char link_mode; /* mapping policy to operstate */ unsigned int mtu; /* interface MTU value */ //最大传输单元 unsigned short type; /* interface hardware type */ //硬件接口的类型 unsigned short hard_header_len; /* hardware hdr length */ //网络设备的硬件头长度 /* extra head- and tailroom the hardware may need, but not in all cases * can this be guaranteed, especially tailroom. Some cases also use * LL_MAX_HEADER instead to allocate the skb. */ unsigned short needed_headroom; unsigned short needed_tailroom; /* Interface address info. */ unsigned char perm_addr[MAX_ADDR_LEN]; /* permanent hw address */ unsigned char addr_assign_type; /* hw address assignment type */ unsigned char addr_len; /* hardware address length */ unsigned short dev_id; /* for shared network cards */ spinlock_t addr_list_lock; struct netdev_hw_addr_list uc; /* Unicast mac addresses */ struct netdev_hw_addr_list mc; /* Multicast mac addresses */ int uc_promisc; unsigned int promiscuity; unsigned int allmulti; /* Protocol specific pointers */ #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE) struct vlan_group __rcu *vlgrp; /* VLAN group */ #endif #ifdef CONFIG_NET_DSA void *dsa_ptr; /* dsa specific data */ #endif void *atalk_ptr; /* AppleTalk link */ struct in_device __rcu *ip_ptr; /* IPv4 specific data */ void *dn_ptr; /* DECnet specific data */ struct inet6_dev __rcu *ip6_ptr; /* IPv6 specific data */ void *ec_ptr; /* Econet specific data */ void *ax25_ptr; /* AX.25 specific data */ struct wireless_dev *ieee80211_ptr; /* IEEE 802.11 specific data, assign before registering */ /* * Cache lines mostly used on receive path (including eth_type_trans()) */ unsigned long last_rx; /* Time of last Rx * This should not be set in * drivers, unless really needed, * because network stack (bonding) * use it if/when necessary, to * avoid dirtying this cache line. */ struct net_device *master; /* Pointer to master device of a group, * which this device is member of. */ /* Interface address info used in eth_type_trans() */ unsigned char *dev_addr; /* hw address, (before bcast //设备的硬件地址，即MAC地址 because most packets are unicast) */ struct netdev_hw_addr_list dev_addrs; /* list of device //设备的广播地址 hw addresses */ unsigned char broadcast[MAX_ADDR_LEN]; /* hw bcast add */ #ifdef CONFIG_RPS struct kset *queues_kset; struct netdev_rx_queue *_rx; /* Number of RX queues allocated at register_netdev() time */ unsigned int num_rx_queues; /* Number of RX queues currently active in device */ unsigned int real_num_rx_queues; #endif rx_handler_func_t *rx_handler; void *rx_handler_data; struct netdev_queue __rcu *ingress_queue; /* * Cache lines mostly used on transmit path */ struct netdev_queue *_tx ____cacheline_aligned_in_smp; /* Number of TX queues allocated at alloc_netdev_mq() time */ unsigned int num_tx_queues; /* Number of TX queues currently active in device */ unsigned int real_num_tx_queues; /* root qdisc from userspace point of view */ struct Qdisc *qdisc; unsigned long tx_queue_len; /* Max frames per queue allowed */ spinlock_t tx_global_lock; /* These may be needed for future network-power-down code. */ /* * trans_start here is expensive for high speed devices on SMP, * please use netdev_queue->trans_start instead. */ unsigned long trans_start; /* Time (in jiffies) of last Tx */ int watchdog_timeo; /* used by dev_watchdog() */ struct timer_list watchdog_timer; /* Number of references to this device */ int __percpu *pcpu_refcnt; /* delayed register/unregister */ struct list_head todo_list; /* device index hash chain */ struct hlist_node index_hlist; struct list_head link_watch_list; /* register/unregister state machine */ enum { NETREG_UNINITIALIZED=0, NETREG_REGISTERED, /* completed register_netdevice */ NETREG_UNREGISTERING, /* called unregister_netdevice */ NETREG_UNREGISTERED, /* completed unregister todo */ NETREG_RELEASED, /* called free_netdev */ NETREG_DUMMY, /* dummy device for NAPI poll */ } reg_state:16; enum { RTNL_LINK_INITIALIZED, RTNL_LINK_INITIALIZING, } rtnl_link_state:16; /* Called from unregister, can be used to call free_netdev */ void (*destructor)(struct net_device *dev); #ifdef CONFIG_NETPOLL struct netpoll_info *npinfo; #endif #ifdef CONFIG_NET_NS /* Network namespace this network device is inside */ struct net *nd_net; #endif /* mid-layer private */ union { void *ml_priv; struct pcpu_lstats __percpu *lstats; /* loopback stats */ struct pcpu_tstats __percpu *tstats; /* tunnel stats */ struct pcpu_dstats __percpu *dstats; /* dummy stats */ }; /* GARP */ struct garp_port __rcu *garp_port; /* class/net/name entry */ struct device dev; /* space for optional device, statistics, and wireless sysfs groups */ const struct attribute_group *sysfs_groups[4]; /* rtnetlink link ops */ const struct rtnl_link_ops *rtnl_link_ops; /* VLAN feature mask */ unsigned long vlan_features; /* for setting kernel sock attribute on TCP connection setup */ #define GSO_MAX_SIZE 65536 unsigned int gso_max_size; #ifdef CONFIG_DCB /* Data Center Bridging netlink ops */ const struct dcbnl_rtnl_ops *dcbnl_ops; #endif #if defined(CONFIG_FCOE) || defined(CONFIG_FCOE_MODULE) /* max exchange id for FCoE LRO by ddp */ unsigned int fcoe_ddp_xid; #endif /* n-tuple filter list attached to this device */ struct ethtool_rx_ntuple_list ethtool_ntuple_list; /* phy device may attach itself for hardware timestamping */ struct phy_device *phydev; };
http://my.oschina.net/lvyi/blog/325785