6f23ee1fef
This patch adds a new, "binary" API in addition to the old, text API usbmon had before. The new API allows for less CPU use, and it allows to capture all data from a packet where old API only captured 32 bytes at most. There are some limitations and conditions to this, e.g. in case someone constructs a URB with 1GB of data, it's not likely to be captured, because even the huge buffers of the new reader are finite. Nonetheless, I expect this new capability to capture all data for all real life scenarios. The downside is, a special user mode application is required where cat(1) worked before. I have sample code at http://people.redhat.com/zaitcev/linux/ and Paolo Abeni is working on patching libpcap. This patch was initially written by Paolo and later I tweaked it, and we had a little back-and-forth. So this is a jointly authored patch, but I am submitting this I am responsible for the bugs. Signed-off-by: Paolo Abeni <paolo.abeni@email.it> Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/*
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* The USB Monitor, inspired by Dave Harding's USBMon.
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*
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* mon_dma.c: Library which snoops on DMA areas.
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*
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* Copyright (C) 2005 Pete Zaitcev (zaitcev@redhat.com)
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*/
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/highmem.h>
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#include <asm/page.h>
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#include <linux/usb.h> /* Only needed for declarations in usb_mon.h */
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#include "usb_mon.h"
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/*
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* PC-compatibles, are, fortunately, sufficiently cache-coherent for this.
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*/
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#if defined(__i386__) || defined(__x86_64__) /* CONFIG_ARCH_I386 doesn't exit */
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#define MON_HAS_UNMAP 1
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#define phys_to_page(phys) pfn_to_page((phys) >> PAGE_SHIFT)
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char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)
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{
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struct page *pg;
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unsigned long flags;
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unsigned char *map;
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unsigned char *ptr;
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/*
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* On i386, a DMA handle is the "physical" address of a page.
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* In other words, the bus address is equal to physical address.
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* There is no IOMMU.
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*/
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pg = phys_to_page(dma_addr);
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/*
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* We are called from hardware IRQs in case of callbacks.
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* But we can be called from softirq or process context in case
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* of submissions. In such case, we need to protect KM_IRQ0.
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*/
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local_irq_save(flags);
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map = kmap_atomic(pg, KM_IRQ0);
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ptr = map + (dma_addr & (PAGE_SIZE-1));
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memcpy(dst, ptr, len);
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kunmap_atomic(map, KM_IRQ0);
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local_irq_restore(flags);
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return 0;
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}
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void mon_dmapeek_vec(const struct mon_reader_bin *rp,
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unsigned int offset, dma_addr_t dma_addr, unsigned int length)
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{
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unsigned long flags;
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unsigned int step_len;
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struct page *pg;
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unsigned char *map;
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unsigned long page_off, page_len;
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local_irq_save(flags);
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while (length) {
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/* compute number of bytes we are going to copy in this page */
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step_len = length;
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page_off = dma_addr & (PAGE_SIZE-1);
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page_len = PAGE_SIZE - page_off;
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if (page_len < step_len)
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step_len = page_len;
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/* copy data and advance pointers */
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pg = phys_to_page(dma_addr);
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map = kmap_atomic(pg, KM_IRQ0);
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offset = mon_copy_to_buff(rp, offset, map + page_off, step_len);
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kunmap_atomic(map, KM_IRQ0);
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dma_addr += step_len;
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length -= step_len;
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}
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local_irq_restore(flags);
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}
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#endif /* __i386__ */
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#ifndef MON_HAS_UNMAP
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char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len)
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{
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return 'D';
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}
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void mon_dmapeek_vec(const struct mon_reader_bin *rp,
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unsigned int offset, dma_addr_t dma_addr, unsigned int length)
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{
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;
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}
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#endif /* MON_HAS_UNMAP */
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