mirror of
https://github.com/checkpoint-restore/criu.git
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c5eb61e866
Currently it can only work with stream sockets, which have no skbs in queues (listening or established -- both work OK). The cpt part uses the sock_diag engine that was merged to Dave recently to collect sockets. Then it dumps sockets by checking the filesystem ID of a failed-to-open through /proc/pid/fd descriptors (sockets do not allow for such tricks with opens through proc) against SOCKFS_TYPE. The rst part is more tricky. Listen sockets are just restored, this is simple. Connected sockets are restored like this: 1. One end establishes a listening anon socket at the desired descriptor; 2. The other end just creates a socket at the desired descriptor; 3. All sockets, that are to be connect()-ed call connect. Unix sockets do not block connect() till the accept() time and thus we continue with... 4. ... all listening sockets call accept() and ... dup2 the new fd into the accepting end. There's a problem with this approach -- socket names are not preserved, but looking into our OpenVZ implementation I think this is OK for existing apps. What should be done next is: 1. Need to merge the file IDs patches in our tree and make Andrey to support files sharing. This will solve the sk = socket(); fork(); case. Currently it simply doesn't work :( 2. Need to add support for DGRAM sockets -- I wrote comment how to do it in the can_dump_unix_sk() 3. Need to add support for in-flight connections 4. Implement support for UDP sockets (quite simple) 5. Implement support for listening TCP sockets (also not very complex) 6. Implement support for connected TCP scokets (hard one, Tejun's patches are not very good for this from my POV) Cyrill, plz, apply this patch and put the above descriptions onto wiki docs (do we have the plans page yet?). Andrey, plz, take care of unix sockets tests in zdtm. Most likely it won't work till you do the shared files support for sockets. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
46 lines
1.9 KiB
C
46 lines
1.9 KiB
C
#ifndef __LINUX_RTNETLINK_H
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#define __LINUX_RTNETLINK_H
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struct rtattr {
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unsigned short rta_len;
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unsigned short rta_type;
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};
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/* Macros to handle rtattributes */
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#define RTA_ALIGNTO 4
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#define RTA_ALIGN(len) ( ((len)+RTA_ALIGNTO-1) & ~(RTA_ALIGNTO-1) )
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#define RTA_OK(rta,len) ((len) >= (int)sizeof(struct rtattr) && \
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(rta)->rta_len >= sizeof(struct rtattr) && \
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(rta)->rta_len <= (len))
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#define RTA_NEXT(rta,attrlen) ((attrlen) -= RTA_ALIGN((rta)->rta_len), \
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(struct rtattr*)(((char*)(rta)) + RTA_ALIGN((rta)->rta_len)))
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#define RTA_LENGTH(len) (RTA_ALIGN(sizeof(struct rtattr)) + (len))
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#define RTA_SPACE(len) RTA_ALIGN(RTA_LENGTH(len))
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#define RTA_DATA(rta) ((void*)(((char*)(rta)) + RTA_LENGTH(0)))
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#define RTA_PAYLOAD(rta) ((int)((rta)->rta_len) - RTA_LENGTH(0))
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#define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
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#define NLMSG_HDRLEN ((int) NLMSG_ALIGN(sizeof(struct nlmsghdr)))
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#define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(NLMSG_HDRLEN))
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#define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
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#define NLMSG_DATA(nlh) ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
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#define NLMSG_NEXT(nlh,len) ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
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(struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
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#define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
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(nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
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(nlh)->nlmsg_len <= (len))
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#define NLMSG_PAYLOAD(nlh,len) ((nlh)->nlmsg_len - NLMSG_SPACE((len)))
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#define NLMSG_NOOP 0x1 /* Nothing. */
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#define NLMSG_ERROR 0x2 /* Error */
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#define NLMSG_DONE 0x3 /* End of a dump */
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#define NLMSG_OVERRUN 0x4 /* Data lost */
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#define NLMSG_MIN_TYPE 0x10 /* < 0x10: reserved control messages */
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int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len);
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int nlmsg_receive(char *buf, int len, int (*cb)(struct nlmsghdr *));
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#endif
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