The Tor Browser: netwerk/sctp/src/user_mbuf.h@ac0c01689b40 (annotated)

netwerk/sctp/src/user_mbuf.h@ac0c01689b40 (annotated)

netwerk/sctp/src/user_mbuf.h

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
permissions: -rwxr-xr-x

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /*-
  * Copyright (c) 1982, 1986, 1988, 1993
  *      The Regents of the University of California.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
  */
 #ifndef _USER_MBUF_H_
 #define _USER_MBUF_H_
 /* __Userspace__ header file for mbufs */
 #include <stdio.h>
 #if !defined(SCTP_SIMPLE_ALLOCATOR)
 #include "umem.h"
 #endif
 #include "user_malloc.h"
 #include "netinet/sctp_os_userspace.h"
 #define USING_MBUF_CONSTRUCTOR 0
 /* For Linux */
 #ifndef MSIZE
 #define MSIZE 256
 /* #define MSIZE 1024 */
 #endif
 #ifndef MCLBYTES
 #define MCLBYTES 2048
 #endif
 struct mbuf * m_gethdr(int how, short type);
 struct mbuf * m_get(int how, short type);
 struct mbuf * m_free(struct mbuf *m);
 void m_clget(struct mbuf *m, int how);
 /* mbuf initialization function */
 void mbuf_init(void *);
 #define	M_MOVE_PKTHDR(to, from)	m_move_pkthdr((to), (from))
 #define	MGET(m, how, type)	((m) = m_get((how), (type)))
 #define	MGETHDR(m, how, type)	((m) = m_gethdr((how), (type)))
 #define	MCLGET(m, how)		m_clget((m), (how))
 #define M_HDR_PAD ((sizeof(intptr_t)==4) ? 2 : 6) /* modified for __Userspace__ */
 /* Length to m_copy to copy all. */
 #define	M_COPYALL	1000000000
 /* umem_cache_t is defined in user_include/umem.h as
  * typedef struct umem_cache umem_cache_t;
  * Note:umem_zone_t is a pointer.
  */
 #if defined(SCTP_SIMPLE_ALLOCATOR)
 typedef size_t sctp_zone_t;
 #else
 typedef umem_cache_t *sctp_zone_t;
 #endif
 extern sctp_zone_t zone_mbuf;
 extern sctp_zone_t zone_clust;
 extern sctp_zone_t zone_ext_refcnt;
 /*-
  * Macros for type conversion:
  * mtod(m, t)	-- Convert mbuf pointer to data pointer of correct type.
  * dtom(x)	-- Convert data pointer within mbuf to mbuf pointer (XXX).
  */
 #define	mtod(m, t)	((t)((m)->m_data))
 #define	dtom(x)		((struct mbuf *)((intptr_t)(x) & ~(MSIZE-1)))
 struct mb_args {
 	int	flags;	/* Flags for mbuf being allocated */
 	short	type;	/* Type of mbuf being allocated */
 };
 struct clust_args {
 	struct mbuf * parent_mbuf;
 };
 struct mbuf *    m_split(struct mbuf *, int, int);
 void             m_cat(struct mbuf *m, struct mbuf *n);
 void		 m_adj(struct mbuf *, int);
 void  mb_free_ext(struct mbuf *);
 void  m_freem(struct mbuf *);
 struct m_tag	*m_tag_alloc(u_int32_t, int, int, int);
 struct mbuf	*m_copym(struct mbuf *, int, int, int);
 void		 m_copyback(struct mbuf *, int, int, caddr_t);
 struct mbuf	*m_pullup(struct mbuf *, int);
 struct mbuf	*m_pulldown(struct mbuf *, int off, int len, int *offp);
 int		 m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
 struct m_tag	*m_tag_copy(struct m_tag *, int);
 int		 m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
 struct mbuf	*m_prepend(struct mbuf *, int, int);
 void		 m_copydata(const struct mbuf *, int, int, caddr_t);
 #define MBUF_MEM_NAME "mbuf"
 #define MBUF_CLUSTER_MEM_NAME "mbuf_cluster"
 #define	MBUF_EXTREFCNT_MEM_NAME	"mbuf_ext_refcnt"
 #define	MT_NOINIT	255	/* Not a type but a flag to allocate
 				   a non-initialized mbuf */
 /*
  * General mbuf allocator statistics structure.
  * __Userspace__ mbstat may be useful for gathering statistics.
  * In the kernel many of these statistics are no longer used as
  * they track allocator statistics through kernel UMA's built in statistics mechanism.
  */
 struct mbstat {
 	u_long	m_mbufs;	/* XXX */
 	u_long	m_mclusts;	/* XXX */
 	u_long	m_drain;	/* times drained protocols for space */
 	u_long	m_mcfail;	/* XXX: times m_copym failed */
 	u_long	m_mpfail;	/* XXX: times m_pullup failed */
 	u_long	m_msize;	/* length of an mbuf */
 	u_long	m_mclbytes;	/* length of an mbuf cluster */
 	u_long	m_minclsize;	/* min length of data to allocate a cluster */
 	u_long	m_mlen;		/* length of data in an mbuf */
 	u_long	m_mhlen;	/* length of data in a header mbuf */
 	/* Number of mbtypes (gives # elems in mbtypes[] array: */
 	short	m_numtypes;
 	/* XXX: Sendfile stats should eventually move to their own struct */
 	u_long	sf_iocnt;	/* times sendfile had to do disk I/O */
 	u_long	sf_allocfail;	/* times sfbuf allocation failed */
 	u_long	sf_allocwait;	/* times sfbuf allocation had to wait */
 };
 /*
  * Mbufs are of a single size, MSIZE (sys/param.h), which includes overhead.
  * An mbuf may add a single "mbuf cluster" of size MCLBYTES (also in
  * sys/param.h), which has no additional overhead and is used instead of the
  * internal data area; this is done when at least MINCLSIZE of data must be
  * stored.  Additionally, it is possible to allocate a separate buffer
  * externally and attach it to the mbuf in a way similar to that of mbuf
  * clusters.
  */
 #define	MLEN		((int)(MSIZE - sizeof(struct m_hdr)))	/* normal data len */
 #define	MHLEN		((int)(MLEN - sizeof(struct pkthdr)))	/* data len w/pkthdr */
 #define	MINCLSIZE	((int)(MHLEN + 1))	/* smallest amount to put in cluster */
 #define	M_MAXCOMPRESS	(MHLEN / 2)	/* max amount to copy for compression */
 /*
  * Header present at the beginning of every mbuf.
  */
 struct m_hdr {
 	struct mbuf	*mh_next;	/* next buffer in chain */
 	struct mbuf	*mh_nextpkt;	/* next chain in queue/record */
 	caddr_t		 mh_data;	/* location of data */
 	int		 mh_len;	/* amount of data in this mbuf */
 	int		 mh_flags;	/* flags; see below */
 	short		 mh_type;	/* type of data in this mbuf */
 	uint8_t          pad[M_HDR_PAD];/* word align                  */
 };
 /*
  * Packet tag structure (see below for details).
  */
 struct m_tag {
 	SLIST_ENTRY(m_tag)	m_tag_link;	/* List of packet tags */
 	u_int16_t		m_tag_id;	/* Tag ID */
 	u_int16_t		m_tag_len;	/* Length of data */
 	u_int32_t		m_tag_cookie;	/* ABI/Module ID */
 	void			(*m_tag_free)(struct m_tag *);
 };
 /*
  * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
  */
 struct pkthdr {
 	struct ifnet	*rcvif;		/* rcv interface */
 	/* variables for ip and tcp reassembly */
 	void		*header;	/* pointer to packet header */
 	int		 len;		/* total packet length */
 	/* variables for hardware checksum */
 	int		 csum_flags;	/* flags regarding checksum */
 	int		 csum_data;	/* data field used by csum routines */
 	u_int16_t	 tso_segsz;	/* TSO segment size */
 	u_int16_t	 ether_vtag;	/* Ethernet 802.1p+q vlan tag */
 	SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
 };
 /*
  * Description of external storage mapped into mbuf; valid only if M_EXT is
  * set.
  */
 struct m_ext {
 	caddr_t		 ext_buf;	/* start of buffer */
 	void		(*ext_free)	/* free routine if not the usual */
 			    (void *, void *);
 	void		*ext_args;	/* optional argument pointer */
 	u_int		 ext_size;	/* size of buffer, for ext_free */
 	volatile u_int	*ref_cnt;	/* pointer to ref count info */
 	int		 ext_type;	/* type of external storage */
 };
 /*
  * The core of the mbuf object along with some shortcut defined for practical
  * purposes.
  */
 struct mbuf {
 	struct m_hdr	m_hdr;
 	union {
 		struct {
 			struct pkthdr	MH_pkthdr;	/* M_PKTHDR set */
 			union {
 				struct m_ext	MH_ext;	/* M_EXT set */
 				char		MH_databuf[MHLEN];
 			} MH_dat;
 		} MH;
 		char	M_databuf[MLEN];		/* !M_PKTHDR, !M_EXT */
 	} M_dat;
 };
 #define	m_next		m_hdr.mh_next
 #define	m_len		m_hdr.mh_len
 #define	m_data		m_hdr.mh_data
 #define	m_type		m_hdr.mh_type
 #define	m_flags		m_hdr.mh_flags
 #define	m_nextpkt	m_hdr.mh_nextpkt
 #define	m_act		m_nextpkt
 #define	m_pkthdr	M_dat.MH.MH_pkthdr
 #define	m_ext		M_dat.MH.MH_dat.MH_ext
 #define	m_pktdat	M_dat.MH.MH_dat.MH_databuf
 #define	m_dat		M_dat.M_databuf
 /*
  * mbuf flags.
  */
 #define	M_EXT		0x0001	/* has associated external storage */
 #define	M_PKTHDR	0x0002	/* start of record */
 #define	M_EOR		0x0004	/* end of record */
 #define	M_RDONLY	0x0008	/* associated data is marked read-only */
 #define	M_PROTO1	0x0010	/* protocol-specific */
 #define	M_PROTO2	0x0020	/* protocol-specific */
 #define	M_PROTO3	0x0040	/* protocol-specific */
 #define	M_PROTO4	0x0080	/* protocol-specific */
 #define	M_PROTO5	0x0100	/* protocol-specific */
 #define	M_SKIP_FIREWALL	0x4000	/* skip firewall processing */
 #define	M_FREELIST	0x8000	/* mbuf is on the free list */
 /*
  * Flags copied when copying m_pkthdr.
  */
 #define	M_COPYFLAGS	(M_PKTHDR|M_EOR|M_RDONLY|M_PROTO1|M_PROTO1|M_PROTO2|\
 			    M_PROTO3|M_PROTO4|M_PROTO5|M_SKIP_FIREWALL|\
 			    M_BCAST|M_MCAST|M_FRAG|M_FIRSTFRAG|M_LASTFRAG|\
 			    M_VLANTAG|M_PROMISC)
 /*
  * mbuf pkthdr flags (also stored in m_flags).
  */
 #define	M_BCAST		0x0200	/* send/received as link-level broadcast */
 #define	M_MCAST		0x0400	/* send/received as link-level multicast */
 #define	M_FRAG		0x0800	/* packet is a fragment of a larger packet */
 #define	M_FIRSTFRAG	0x1000	/* packet is first fragment */
 #define	M_LASTFRAG	0x2000	/* packet is last fragment */
 #define	M_VLANTAG	0x10000	/* ether_vtag is valid */
 #define	M_PROMISC	0x20000	/* packet was not for us */
 #define	M_NOFREE	0x40000	/* do not free mbuf - it is embedded in the cluster */
 /*
  * External buffer types: identify ext_buf type.
  */
 #define	EXT_CLUSTER	1	/* mbuf cluster */
 #define	EXT_SFBUF	2	/* sendfile(2)'s sf_bufs */
 #define	EXT_JUMBOP	3	/* jumbo cluster 4096 bytes */
 #define	EXT_JUMBO9	4	/* jumbo cluster 9216 bytes */
 #define	EXT_JUMBO16	5	/* jumbo cluster 16184 bytes */
 #define	EXT_PACKET	6	/* mbuf+cluster from packet zone */
 #define	EXT_MBUF	7	/* external mbuf reference (M_IOVEC) */
 #define	EXT_NET_DRV	100	/* custom ext_buf provided by net driver(s) */
 #define	EXT_MOD_TYPE	200	/* custom module's ext_buf type */
 #define	EXT_DISPOSABLE	300	/* can throw this buffer away w/page flipping */
 #define	EXT_EXTREF	400	/* has externally maintained ref_cnt ptr */
 /*
  * mbuf types.
  */
 #define	MT_NOTMBUF	0	/* USED INTERNALLY ONLY! Object is not mbuf */
 #define	MT_DATA		1	/* dynamic (data) allocation */
 #define	MT_HEADER	MT_DATA	/* packet header, use M_PKTHDR instead */
 #define	MT_SONAME	8	/* socket name */
 #define	MT_CONTROL	14	/* extra-data protocol message */
 #define	MT_OOBDATA	15	/* expedited data  */
 #define	MT_NTYPES	16	/* number of mbuf types for mbtypes[] */
 #define	MT_NOINIT	255	/* Not a type but a flag to allocate
 				   a non-initialized mbuf */
 /*
  * __Userspace__ flags like M_NOWAIT are defined in malloc.h
  * Flags like these are used in functions like uma_zalloc()
  * but don't have an equivalent in userland umem
  * Flags specifying how an allocation should be made.
  *
  * The flag to use is as follows:
  * - M_DONTWAIT or M_NOWAIT from an interrupt handler to not block allocation.
  * - M_WAIT or M_WAITOK or M_TRYWAIT from wherever it is safe to block.
  *
  * M_DONTWAIT/M_NOWAIT means that we will not block the thread explicitly and
  * if we cannot allocate immediately we may return NULL, whereas
  * M_WAIT/M_WAITOK/M_TRYWAIT means that if we cannot allocate resources we
  * will block until they are available, and thus never return NULL.
  *
  * XXX Eventually just phase this out to use M_WAITOK/M_NOWAIT.
  */
 #define	MBTOM(how)	(how)
 void		 m_tag_delete(struct mbuf *, struct m_tag *);
 void		 m_tag_delete_chain(struct mbuf *, struct m_tag *);
 void		 m_move_pkthdr(struct mbuf *, struct mbuf *);
 void		 m_tag_free_default(struct m_tag *);
 extern int max_linkhdr;    /* Largest link-level header */
 extern int max_protohdr; /* Size of largest protocol layer header. See user_mbuf.c */
 extern struct mbstat	mbstat;		/* General mbuf stats/infos */
 /*
  * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can
  * be both the local data payload, or an external buffer area, depending on
  * whether M_EXT is set).
  */
 #define	M_WRITABLE(m)	(!((m)->m_flags & M_RDONLY) &&			\
 			 (!(((m)->m_flags & M_EXT)) ||			\
 			 (*((m)->m_ext.ref_cnt) == 1)) )		\
 /*
  * Compute the amount of space available before the current start of data in
  * an mbuf.
  *
  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  * of checking writability of the mbuf data area rests solely with the caller.
  */
 #define	M_LEADINGSPACE(m)						\
 	((m)->m_flags & M_EXT ?						\
 	    (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0):	\
 	    (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat :	\
 	    (m)->m_data - (m)->m_dat)
 /*
  * Compute the amount of space available after the end of data in an mbuf.
  *
  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  * of checking writability of the mbuf data area rests solely with the caller.
  */
 #define	M_TRAILINGSPACE(m)						\
 	((m)->m_flags & M_EXT ?						\
 	    (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size	\
 		- ((m)->m_data + (m)->m_len) : 0) :			\
 	    &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
 /*
  * Arrange to prepend space of size plen to mbuf m.  If a new mbuf must be
  * allocated, how specifies whether to wait.  If the allocation fails, the
  * original mbuf chain is freed and m is set to NULL.
  */
 #define	M_PREPEND(m, plen, how) do {					\
 	struct mbuf **_mmp = &(m);					\
 	struct mbuf *_mm = *_mmp;					\
 	int _mplen = (plen);						\
 	int __mhow = (how);						\
 									\
 	if (M_LEADINGSPACE(_mm) >= _mplen) {				\
 		_mm->m_data -= _mplen;					\
 		_mm->m_len += _mplen;					\
 	} else								\
 		_mm = m_prepend(_mm, _mplen, __mhow);			\
 	if (_mm != NULL && _mm->m_flags & M_PKTHDR)			\
 		_mm->m_pkthdr.len += _mplen;				\
 	*_mmp = _mm;							\
 } while (0)
 /*
  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place an
  * object of the specified size at the end of the mbuf, longword aligned.
  */
 #define	M_ALIGN(m, len) do {						\
         KASSERT(!((m)->m_flags & (M_PKTHDR|M_EXT)),                     \
                 ("%s: M_ALIGN not normal mbuf", __func__));             \
         KASSERT((m)->m_data == (m)->m_dat,                              \
                 ("%s: M_ALIGN not a virgin mbuf", __func__));           \
 	(m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1);		\
 } while (0)
 /*
  * As above, for mbufs allocated with m_gethdr/MGETHDR or initialized by
  * M_DUP/MOVE_PKTHDR.
  */
 #define	MH_ALIGN(m, len) do {						\
         KASSERT((m)->m_flags & M_PKTHDR && !((m)->m_flags & M_EXT),     \
                 ("%s: MH_ALIGN not PKTHDR mbuf", __func__));            \
         KASSERT((m)->m_data == (m)->m_pktdat,                           \
                 ("%s: MH_ALIGN not a virgin mbuf", __func__));          \
 	(m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1);		\
 } while (0)
 #endif

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netwerk/sctp/src/user_mbuf.h@ac0c01689b40 (annotated)

netwerk/sctp/src/user_mbuf.h