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Diffstat (limited to 'src/tcpedit/dlt.c')
| -rw-r--r-- | src/tcpedit/dlt.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/src/tcpedit/dlt.c b/src/tcpedit/dlt.c new file mode 100644 index 0000000..a6f15d0 --- /dev/null +++ b/src/tcpedit/dlt.c @@ -0,0 +1,171 @@ +/* $Id: dlt.c 2423 2010-03-13 07:09:49Z aturner $ */ + +/* + * Copyright (c) 2001-2010 Aaron Turner. + * 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 names of the copyright owners 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 ``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 AUTHORS OR COPYRIGHT HOLDERS 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. + */ +#include <assert.h> +#include "config.h" +#include "defines.h" +#include "tcpedit-int.h" +#include "dlt.h" + +/** + * takes in a libpcap DLT_ type and returns the length of the layer2 header + * returns -1 for unsupported DLT + */ +int +dlt2layer2len(tcpedit_t *tcpedit, int dlt) +{ + assert(tcpedit); + int len; + switch(dlt) { + /* + case DLT_USER: + len = tcpedit->l2.len; + break; + */ + case DLT_NULL: + len = 2; + break; + + case DLT_RAW: + len = 0; + break; + + case DLT_EN10MB: + len = 12; + break; + /* + case DLT_VLAN: + len = 14; + break; + */ + case DLT_LINUX_SLL: + len = 16; + break; + + case DLT_C_HDLC: + len = 4; + break; + + default: + tcpedit_seterr(tcpedit, "Invalid DLT Type: %d", dlt); + len = -1; + } + + return len; +} + +/** + * each DLT type may require one or more user specified Layer 2 field + * to be able to rewrite it as plain ethernet DLT_EN10MB + * returns -1 on error or >= 0 on success + */ +int +dltrequires(tcpedit_t *tcpedit, int dlt) +{ + assert(tcpedit); + int req = TCPEDIT_DLT_OK; // no change required by default + + switch(dlt) { + case DLT_EN10MB: +/* case DLT_USER: + case DLT_VLAN: */ + /* we have everthing we need in the original packet */ + break; + + case DLT_NULL: + case DLT_RAW: + case DLT_C_HDLC: + req = TCPEDIT_DLT_SRC + TCPEDIT_DLT_DST; + /* we just have the proto */ + break; + + case DLT_LINUX_SLL: + /* we have proto & SRC address */ + req = TCPEDIT_DLT_DST; + break; + + default: + tcpedit_seterr(tcpedit, "Invalid DLT Type: %d", dlt); + req = -1; + } + + return req; +} + +/** + * returns the default MTU size for the given DLT type. Returns -1 + * for invalid DLT + */ +int +dlt2mtu(tcpedit_t *tcpedit, int dlt) +{ + int mtu; + assert(tcpedit); + switch (dlt) { +/* case DLT_VLAN: + case DLT_USER: */ + case DLT_EN10MB: + case DLT_RAW: + case DLT_C_HDLC: + mtu = 1500; + break; + + case DLT_LINUX_SLL: + mtu = 16436; + break; + + case DLT_LOOP: + mtu = 16384; + break; + + default: + tcpedit_seterr(tcpedit, "Invalid DLT Type: %d", dlt); + mtu = -1; + break; + } + + return mtu; +} + +/** + * Returns the current layer 2 len based on the + * DLT of the pcap or the --dlink value or -1 on error. + * You need to call this function AFTER rewriting the layer 2 header + * for it to be at all useful. + */ +int +layer2len(tcpedit_t *tcpedit) +{ + assert(tcpedit); + + return tcpedit->dlt_ctx->l2len; +} + |