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8402a31dd8
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293
("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
263 lines
8.6 KiB
C
263 lines
8.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef _CCID_H
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#define _CCID_H
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/*
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* net/dccp/ccid.h
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*
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* An implementation of the DCCP protocol
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* CCID infrastructure
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*/
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#include <net/sock.h>
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#include <linux/compiler.h>
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#include <linux/dccp.h>
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#include <linux/list.h>
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#include <linux/module.h>
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/* maximum value for a CCID (RFC 4340, 19.5) */
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#define CCID_MAX 255
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#define CCID_SLAB_NAME_LENGTH 32
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struct tcp_info;
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/**
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* struct ccid_operations - Interface to Congestion-Control Infrastructure
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*
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* @ccid_id: numerical CCID ID (up to %CCID_MAX, cf. table 5 in RFC 4340, 10.)
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* @ccid_ccmps: the CCMPS including network/transport headers (0 when disabled)
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* @ccid_name: alphabetical identifier string for @ccid_id
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* @ccid_hc_{r,t}x_slab: memory pool for the receiver/sender half-connection
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* @ccid_hc_{r,t}x_obj_size: size of the receiver/sender half-connection socket
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*
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* @ccid_hc_{r,t}x_init: CCID-specific initialisation routine (before startup)
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* @ccid_hc_{r,t}x_exit: CCID-specific cleanup routine (before destruction)
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* @ccid_hc_rx_packet_recv: implements the HC-receiver side
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* @ccid_hc_{r,t}x_parse_options: parsing routine for CCID/HC-specific options
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* @ccid_hc_{r,t}x_insert_options: insert routine for CCID/HC-specific options
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* @ccid_hc_tx_packet_recv: implements feedback processing for the HC-sender
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* @ccid_hc_tx_send_packet: implements the sending part of the HC-sender
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* @ccid_hc_tx_packet_sent: does accounting for packets in flight by HC-sender
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* @ccid_hc_{r,t}x_get_info: INET_DIAG information for HC-receiver/sender
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* @ccid_hc_{r,t}x_getsockopt: socket options specific to HC-receiver/sender
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*/
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struct ccid_operations {
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unsigned char ccid_id;
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__u32 ccid_ccmps;
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const char *ccid_name;
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struct kmem_cache *ccid_hc_rx_slab,
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*ccid_hc_tx_slab;
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char ccid_hc_rx_slab_name[CCID_SLAB_NAME_LENGTH];
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char ccid_hc_tx_slab_name[CCID_SLAB_NAME_LENGTH];
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__u32 ccid_hc_rx_obj_size,
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ccid_hc_tx_obj_size;
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/* Interface Routines */
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int (*ccid_hc_rx_init)(struct ccid *ccid, struct sock *sk);
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int (*ccid_hc_tx_init)(struct ccid *ccid, struct sock *sk);
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void (*ccid_hc_rx_exit)(struct sock *sk);
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void (*ccid_hc_tx_exit)(struct sock *sk);
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void (*ccid_hc_rx_packet_recv)(struct sock *sk,
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struct sk_buff *skb);
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int (*ccid_hc_rx_parse_options)(struct sock *sk, u8 pkt,
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u8 opt, u8 *val, u8 len);
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int (*ccid_hc_rx_insert_options)(struct sock *sk,
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struct sk_buff *skb);
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void (*ccid_hc_tx_packet_recv)(struct sock *sk,
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struct sk_buff *skb);
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int (*ccid_hc_tx_parse_options)(struct sock *sk, u8 pkt,
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u8 opt, u8 *val, u8 len);
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int (*ccid_hc_tx_send_packet)(struct sock *sk,
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struct sk_buff *skb);
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void (*ccid_hc_tx_packet_sent)(struct sock *sk,
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unsigned int len);
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void (*ccid_hc_rx_get_info)(struct sock *sk,
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struct tcp_info *info);
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void (*ccid_hc_tx_get_info)(struct sock *sk,
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struct tcp_info *info);
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int (*ccid_hc_rx_getsockopt)(struct sock *sk,
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const int optname, int len,
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u32 __user *optval,
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int __user *optlen);
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int (*ccid_hc_tx_getsockopt)(struct sock *sk,
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const int optname, int len,
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u32 __user *optval,
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int __user *optlen);
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};
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extern struct ccid_operations ccid2_ops;
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#ifdef CONFIG_IP_DCCP_CCID3
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extern struct ccid_operations ccid3_ops;
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#endif
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int ccid_initialize_builtins(void);
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void ccid_cleanup_builtins(void);
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struct ccid {
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struct ccid_operations *ccid_ops;
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char ccid_priv[];
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};
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static inline void *ccid_priv(const struct ccid *ccid)
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{
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return (void *)ccid->ccid_priv;
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}
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bool ccid_support_check(u8 const *ccid_array, u8 array_len);
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int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len);
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int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
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char __user *, int __user *);
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struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx);
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static inline int ccid_get_current_rx_ccid(struct dccp_sock *dp)
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{
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struct ccid *ccid = dp->dccps_hc_rx_ccid;
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if (ccid == NULL || ccid->ccid_ops == NULL)
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return -1;
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return ccid->ccid_ops->ccid_id;
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}
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static inline int ccid_get_current_tx_ccid(struct dccp_sock *dp)
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{
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struct ccid *ccid = dp->dccps_hc_tx_ccid;
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if (ccid == NULL || ccid->ccid_ops == NULL)
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return -1;
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return ccid->ccid_ops->ccid_id;
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}
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void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk);
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void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk);
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/*
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* Congestion control of queued data packets via CCID decision.
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*
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* The TX CCID performs its congestion-control by indicating whether and when a
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* queued packet may be sent, using the return code of ccid_hc_tx_send_packet().
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* The following modes are supported via the symbolic constants below:
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* - timer-based pacing (CCID returns a delay value in milliseconds);
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* - autonomous dequeueing (CCID internally schedules dccps_xmitlet).
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*/
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enum ccid_dequeueing_decision {
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CCID_PACKET_SEND_AT_ONCE = 0x00000, /* "green light": no delay */
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CCID_PACKET_DELAY_MAX = 0x0FFFF, /* maximum delay in msecs */
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CCID_PACKET_DELAY = 0x10000, /* CCID msec-delay mode */
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CCID_PACKET_WILL_DEQUEUE_LATER = 0x20000, /* CCID autonomous mode */
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CCID_PACKET_ERR = 0xF0000, /* error condition */
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};
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static inline int ccid_packet_dequeue_eval(const int return_code)
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{
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if (return_code < 0)
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return CCID_PACKET_ERR;
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if (return_code == 0)
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return CCID_PACKET_SEND_AT_ONCE;
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if (return_code <= CCID_PACKET_DELAY_MAX)
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return CCID_PACKET_DELAY;
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return return_code;
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}
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static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
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struct sk_buff *skb)
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{
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if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
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return ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb);
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return CCID_PACKET_SEND_AT_ONCE;
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}
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static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
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unsigned int len)
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{
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if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL)
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ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, len);
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}
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static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk,
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struct sk_buff *skb)
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{
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if (ccid->ccid_ops->ccid_hc_rx_packet_recv != NULL)
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ccid->ccid_ops->ccid_hc_rx_packet_recv(sk, skb);
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}
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static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
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struct sk_buff *skb)
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{
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if (ccid->ccid_ops->ccid_hc_tx_packet_recv != NULL)
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ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb);
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}
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/**
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* ccid_hc_tx_parse_options - Parse CCID-specific options sent by the receiver
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* @pkt: type of packet that @opt appears on (RFC 4340, 5.1)
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* @opt: the CCID-specific option type (RFC 4340, 5.8 and 10.3)
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* @val: value of @opt
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* @len: length of @val in bytes
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*/
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static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
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u8 pkt, u8 opt, u8 *val, u8 len)
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{
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if (!ccid || !ccid->ccid_ops->ccid_hc_tx_parse_options)
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return 0;
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return ccid->ccid_ops->ccid_hc_tx_parse_options(sk, pkt, opt, val, len);
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}
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/**
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* ccid_hc_rx_parse_options - Parse CCID-specific options sent by the sender
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* Arguments are analogous to ccid_hc_tx_parse_options()
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*/
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static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
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u8 pkt, u8 opt, u8 *val, u8 len)
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{
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if (!ccid || !ccid->ccid_ops->ccid_hc_rx_parse_options)
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return 0;
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return ccid->ccid_ops->ccid_hc_rx_parse_options(sk, pkt, opt, val, len);
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}
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static inline int ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
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struct sk_buff *skb)
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{
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if (ccid->ccid_ops->ccid_hc_rx_insert_options != NULL)
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return ccid->ccid_ops->ccid_hc_rx_insert_options(sk, skb);
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return 0;
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}
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static inline void ccid_hc_rx_get_info(struct ccid *ccid, struct sock *sk,
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struct tcp_info *info)
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{
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if (ccid->ccid_ops->ccid_hc_rx_get_info != NULL)
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ccid->ccid_ops->ccid_hc_rx_get_info(sk, info);
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}
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static inline void ccid_hc_tx_get_info(struct ccid *ccid, struct sock *sk,
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struct tcp_info *info)
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{
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if (ccid->ccid_ops->ccid_hc_tx_get_info != NULL)
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ccid->ccid_ops->ccid_hc_tx_get_info(sk, info);
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}
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static inline int ccid_hc_rx_getsockopt(struct ccid *ccid, struct sock *sk,
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const int optname, int len,
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u32 __user *optval, int __user *optlen)
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{
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int rc = -ENOPROTOOPT;
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if (ccid != NULL && ccid->ccid_ops->ccid_hc_rx_getsockopt != NULL)
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rc = ccid->ccid_ops->ccid_hc_rx_getsockopt(sk, optname, len,
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optval, optlen);
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return rc;
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}
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static inline int ccid_hc_tx_getsockopt(struct ccid *ccid, struct sock *sk,
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const int optname, int len,
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u32 __user *optval, int __user *optlen)
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{
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int rc = -ENOPROTOOPT;
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if (ccid != NULL && ccid->ccid_ops->ccid_hc_tx_getsockopt != NULL)
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rc = ccid->ccid_ops->ccid_hc_tx_getsockopt(sk, optname, len,
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optval, optlen);
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return rc;
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}
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#endif /* _CCID_H */
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