Author: kp Date: Fri Nov 2 15:23:57 2018 New Revision: 340060 URL: https://svnweb.freebsd.org/changeset/base/340060
Log: pf: Count holes rather than fragments for reassembly Avoid traversing the list of fragment entris to check whether the pf(4) reassembly is complete. Instead count the holes that are created when inserting a fragment. If there are no holes left, the fragments are continuous. Obtained from: OpenBSD Differential Revision: https://reviews.freebsd.org/D17732 Modified: head/sys/netpfil/pf/pf_norm.c Modified: head/sys/netpfil/pf/pf_norm.c ============================================================================== --- head/sys/netpfil/pf/pf_norm.c Fri Nov 2 15:03:52 2018 (r340059) +++ head/sys/netpfil/pf/pf_norm.c Fri Nov 2 15:23:57 2018 (r340060) @@ -2,7 +2,7 @@ * SPDX-License-Identifier: BSD-2-Clause * * Copyright 2001 Niels Provos <pro...@citi.umich.edu> - * Copyright 2011 Alexander Bluhm <bl...@openbsd.org> + * Copyright 2011-2018 Alexander Bluhm <bl...@openbsd.org> * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -91,6 +91,7 @@ struct pf_fragment { TAILQ_ENTRY(pf_fragment) frag_next; uint32_t fr_timeout; uint16_t fr_maxlen; /* maximum length of single fragment */ + u_int16_t fr_holes; /* number of holes in the queue */ TAILQ_HEAD(pf_fragq, pf_frent) fr_queue; }; @@ -132,11 +133,11 @@ static void pf_remove_fragment(struct pf_fragment *); static int pf_normalize_tcpopt(struct pf_rule *, struct mbuf *, struct tcphdr *, int, sa_family_t); static struct pf_frent *pf_create_fragment(u_short *); +static int pf_frent_holes(struct pf_frent *frent); static struct pf_fragment *pf_find_fragment(struct pf_fragment_cmp *key, struct pf_frag_tree *tree); static struct pf_fragment *pf_fillup_fragment(struct pf_fragment_cmp *, struct pf_frent *, u_short *); -static int pf_isfull_fragment(struct pf_fragment *); static struct mbuf *pf_join_fragment(struct pf_fragment *); #ifdef INET static void pf_scrub_ip(struct mbuf **, uint32_t, uint8_t, uint8_t); @@ -333,6 +334,39 @@ pf_create_fragment(u_short *reason) return (frent); } +/* + * Calculate the additional holes that were created in the fragment + * queue by inserting this fragment. A fragment in the middle + * creates one more hole by splitting. For each connected side, + * it loses one hole. + * Fragment entry must be in the queue when calling this function. + */ +static int +pf_frent_holes(struct pf_frent *frent) +{ + struct pf_frent *prev = TAILQ_PREV(frent, pf_fragq, fr_next); + struct pf_frent *next = TAILQ_NEXT(frent, fr_next); + int holes = 1; + + if (prev == NULL) { + if (frent->fe_off == 0) + holes--; + } else { + KASSERT(frent->fe_off != 0, ("frent->fe_off != 0")); + if (frent->fe_off == prev->fe_off + prev->fe_len) + holes--; + } + if (next == NULL) { + if (!frent->fe_mff) + holes--; + } else { + KASSERT(frent->fe_mff, ("frent->fe_mff")); + if (next->fe_off == frent->fe_off + frent->fe_len) + holes--; + } + return holes; +} + static struct pf_fragment * pf_fillup_fragment(struct pf_fragment_cmp *key, struct pf_frent *frent, u_short *reason) @@ -384,6 +418,7 @@ pf_fillup_fragment(struct pf_fragment_cmp *key, struct *(struct pf_fragment_cmp *)frag = *key; frag->fr_timeout = time_uptime; frag->fr_maxlen = frent->fe_len; + frag->fr_holes = 1; TAILQ_INIT(&frag->fr_queue); RB_INSERT(pf_frag_tree, &V_pf_frag_tree, frag); @@ -391,6 +426,7 @@ pf_fillup_fragment(struct pf_fragment_cmp *key, struct /* We do not have a previous fragment. */ TAILQ_INSERT_HEAD(&frag->fr_queue, frent, fr_next); + frag->fr_holes += pf_frent_holes(frent); return (frag); } @@ -457,6 +493,7 @@ pf_fillup_fragment(struct pf_fragment_cmp *key, struct /* This fragment is completely overlapped, lose it. */ next = TAILQ_NEXT(after, fr_next); + frag->fr_holes -= pf_frent_holes(after); m_freem(after->fe_m); TAILQ_REMOVE(&frag->fr_queue, after, fr_next); uma_zfree(V_pf_frent_z, after); @@ -466,6 +503,7 @@ pf_fillup_fragment(struct pf_fragment_cmp *key, struct TAILQ_INSERT_HEAD(&frag->fr_queue, frent, fr_next); else TAILQ_INSERT_AFTER(&frag->fr_queue, prev, frent, fr_next); + frag->fr_holes += pf_frent_holes(frent); return (frag); @@ -476,40 +514,6 @@ drop_fragment: return (NULL); } -static int -pf_isfull_fragment(struct pf_fragment *frag) -{ - struct pf_frent *frent, *next; - uint16_t off, total; - - /* Check if we are completely reassembled */ - if (TAILQ_LAST(&frag->fr_queue, pf_fragq)->fe_mff) - return (0); - - /* Maximum data we have seen already */ - total = TAILQ_LAST(&frag->fr_queue, pf_fragq)->fe_off + - TAILQ_LAST(&frag->fr_queue, pf_fragq)->fe_len; - - /* Check if we have all the data */ - off = 0; - for (frent = TAILQ_FIRST(&frag->fr_queue); frent; frent = next) { - next = TAILQ_NEXT(frent, fr_next); - - off += frent->fe_len; - if (off < total && (next == NULL || next->fe_off != off)) { - DPFPRINTF(("missing fragment at %d, next %d, total %d", - off, next == NULL ? -1 : next->fe_off, total)); - return (0); - } - } - DPFPRINTF(("%d < %d?", off, total)); - if (off < total) - return (0); - KASSERT(off == total, ("off == total")); - - return (1); -} - static struct mbuf * pf_join_fragment(struct pf_fragment *frag) { @@ -570,8 +574,10 @@ pf_reassemble(struct mbuf **m0, struct ip *ip, int dir /* The mbuf is part of the fragment entry, no direct free or access */ m = *m0 = NULL; - if (!pf_isfull_fragment(frag)) + if (frag->fr_holes) { + DPFPRINTF(("frag %d, holes %d", frag->fr_id, frag->fr_holes)); return (PF_PASS); /* drop because *m0 is NULL, no error */ + } /* We have all the data */ frent = TAILQ_FIRST(&frag->fr_queue); @@ -654,7 +660,8 @@ pf_reassemble6(struct mbuf **m0, struct ip6_hdr *ip6, /* The mbuf is part of the fragment entry, no direct free or access. */ m = *m0 = NULL; - if (!pf_isfull_fragment(frag)) { + if (frag->fr_holes) { + DPFPRINTF(("frag %d, holes %d", frag->fr_id, frag->fr_holes)); PF_FRAG_UNLOCK(); return (PF_PASS); /* Drop because *m0 is NULL, no error. */ } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
