Author: andre
Date: Thu Oct 31 15:46:10 2013
New Revision: 257455
URL: http://svnweb.freebsd.org/changeset/base/257455
Log:
Make struct ifnet readable and comprehensible again by grouping
and ordering related variables, fields and locks next to each
other. Add more comments to variables.
Over time 'ifnet' has accumlated a lot of additional pointers and
functionality in an unstructured way making it quite hard to read
and understand while obfuscating relationships between fields and
variables.
Quantify the structure size and how bloated it has become.
This is only a mechanical change in preparation for upcoming
work to make ifnet opaque to drivers and to separate out the
interface queuing.
Sponsored by: The FreeBSD Foundation
Modified:
head/sys/net/if_var.h
Modified: head/sys/net/if_var.h
==============================================================================
--- head/sys/net/if_var.h Thu Oct 31 15:27:39 2013 (r257454)
+++ head/sys/net/if_var.h Thu Oct 31 15:46:10 2013 (r257455)
@@ -96,19 +96,42 @@ VNET_DECLARE(struct pfil_head, link_pfil
/*
* Structure defining a network interface.
*
- * (Would like to call this struct ``if'', but C isn't PL/1.)
+ * Size ILP32: 592 (approx)
+ * LP64: 1048 (approx)
*/
-
struct ifnet {
+ /* General book keeping of interface lists. */
+ TAILQ_ENTRY(ifnet) if_link; /* all struct ifnets are chained */
+ LIST_ENTRY(ifnet) if_clones; /* interfaces of a cloner */
+ TAILQ_HEAD(, ifg_list) if_groups; /* linked list of groups per if */
+ /* protected by if_addr_lock */
+ u_char if_alloctype; /* if_type at time of allocation */
+
+ /* Driver and protocol specific information that remains stable. */
void *if_softc; /* pointer to driver state */
+ void *if_llsoftc; /* link layer softc */
void *if_l2com; /* pointer to protocol bits */
- struct vnet *if_vnet; /* pointer to network stack instance */
- TAILQ_ENTRY(ifnet) if_link; /* all struct ifnets are chained */
- char if_xname[IFNAMSIZ]; /* external name (name + unit) */
const char *if_dname; /* driver name */
int if_dunit; /* unit or IF_DUNIT_NONE */
+ u_short if_index; /* numeric abbreviation for this if */
+ short if_index_reserved; /* spare space to grow if_index */
+ char if_xname[IFNAMSIZ]; /* external name (name + unit) */
+ char *if_description; /* interface description */
+
+ /* Variable fields that are touched by the stack and drivers. */
+ int if_flags; /* up/down, broadcast, etc. */
+ int if_capabilities; /* interface features & capabilities */
+ int if_capenable; /* enabled features & capabilities */
+ void *if_linkmib; /* link-type-specific MIB data */
+ size_t if_linkmiblen; /* length of above data */
+ int if_drv_flags; /* driver-managed status flags */
u_int if_refcount; /* reference count */
- struct ifaddrhead if_addrhead; /* linked list of addresses per if */
+ struct ifaltq if_snd; /* output queue (includes altq) */
+ struct if_data if_data; /* type information and statistics */
+ struct task if_linktask; /* task for link change events */
+
+ /* Addresses of different protocol families assigned to this if. */
+ struct rwlock if_addr_lock; /* lock to protect address lists */
/*
* if_addrhead is the list of all addresses associated to
* an interface.
@@ -119,21 +142,29 @@ struct ifnet {
* However, access to the AF_LINK address through this
* field is deprecated. Use if_addr or ifaddr_byindex() instead.
*/
- int if_pcount; /* number of promiscuous listeners */
- struct carp_if *if_carp; /* carp interface structure */
- struct bpf_if *if_bpf; /* packet filter structure */
- u_short if_index; /* numeric abbreviation for this if */
- short if_index_reserved; /* spare space to grow if_index */
- struct ifvlantrunk *if_vlantrunk; /* pointer to 802.1q data */
- int if_flags; /* up/down, broadcast, etc. */
- int if_capabilities; /* interface features & capabilities */
- int if_capenable; /* enabled features & capabilities */
- void *if_linkmib; /* link-type-specific MIB data */
- size_t if_linkmiblen; /* length of above data */
- struct if_data if_data;
+ struct ifaddrhead if_addrhead; /* linked list of addresses per if */
struct ifmultihead if_multiaddrs; /* multicast addresses configured */
int if_amcount; /* number of all-multicast requests */
-/* procedure handles */
+ struct ifaddr *if_addr; /* pointer to link-level address */
+ const u_int8_t *if_broadcastaddr; /* linklevel broadcast bytestring */
+ struct rwlock if_afdata_lock;
+ void *if_afdata[AF_MAX];
+ int if_afdata_initialized;
+
+ /* Additional features hung off the interface. */
+ u_int if_fib; /* interface FIB */
+ struct vnet *if_vnet; /* pointer to network stack instance */
+ struct vnet *if_home_vnet; /* where this ifnet originates from */
+ struct ifvlantrunk *if_vlantrunk; /* pointer to 802.1q data */
+ struct bpf_if *if_bpf; /* packet filter structure */
+ int if_pcount; /* number of promiscuous listeners */
+ void *if_bridge; /* bridge glue */
+ void *if_lagg; /* lagg glue */
+ void *if_pf_kif; /* pf glue */
+ struct carp_if *if_carp; /* carp interface structure */
+ struct label *if_label; /* interface MAC label */
+
+ /* Various procedures of the layer2 encapsulation and drivers. */
int (*if_output) /* output routine (enqueue) */
(struct ifnet *, struct mbuf *, const struct sockaddr *,
struct route *);
@@ -153,39 +184,12 @@ struct ifnet {
(struct ifnet *, struct mbuf *);
void (*if_reassign) /* reassign to vnet routine */
(struct ifnet *, struct vnet *, char *);
- struct vnet *if_home_vnet; /* where this ifnet originates from */
- struct ifaddr *if_addr; /* pointer to link-level address */
- void *if_llsoftc; /* link layer softc */
- int if_drv_flags; /* driver-managed status flags */
- struct ifaltq if_snd; /* output queue (includes altq) */
- const u_int8_t *if_broadcastaddr; /* linklevel broadcast bytestring */
-
- void *if_bridge; /* bridge glue */
-
- struct label *if_label; /* interface MAC label */
-
- /* these are only used by IPv6 */
- void *if_unused[2];
- void *if_afdata[AF_MAX];
- int if_afdata_initialized;
- struct rwlock if_afdata_lock;
- struct task if_linktask; /* task for link change events */
- struct rwlock if_addr_lock; /* lock to protect address lists */
-
- LIST_ENTRY(ifnet) if_clones; /* interfaces of a cloner */
- TAILQ_HEAD(, ifg_list) if_groups; /* linked list of groups per if */
- /* protected by if_addr_lock */
- void *if_pf_kif;
- void *if_lagg; /* lagg glue */
- char *if_description; /* interface description */
- u_int if_fib; /* interface FIB */
- u_char if_alloctype; /* if_type at time of allocation */
+ /* Stuff that's only temporary and doesn't belong here. */
u_int if_hw_tsomax; /* tso burst length limit, the minimum
* is (IP_MAXPACKET / 8).
* XXXAO: Have to find a better place
* for it eventually. */
-
/*
* Spare fields are added so that we can modify sensitive data
* structures without changing the kernel binary interface, and must
@@ -193,6 +197,7 @@ struct ifnet {
*/
char if_cspare[3];
int if_ispare[4];
+ void *if_unused[2];
void *if_pspare[8]; /* 1 netmap, 7 TDB */
};
@@ -521,5 +526,4 @@ void if_deregister_com_alloc(u_char type
LLADDR((struct sockaddr_dl *)((ifp)->if_addr->ifa_addr))
#endif /* _KERNEL */
-
#endif /* !_NET_IF_VAR_H_ */
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