[PATCHv3 0/4] netlink: Extract common code to simplify netlink functions
V2 here: https://www.redhat.com/archives/libvir-list/2021-January/msg00174.html Since V2: - Fix the post process of virNetlinkTalk(). If virNetlinkTalk() succeeds and we got an NLMSG_ERROR packet with the zero-value error, it should be regarded as a success. - Several fixes for the pointer of resp in virNetlinkTalk(). - Minor fixes according to coding style. Shi Lei (4): netlink: Remove invalid flags(NLM_F_CREATE and NLM_F_EXCL) for RTM_DELLINK netlink: Minor changes for macros NETLINK_MSG_[NEST_START|NEST_END|PUT] netlink: Introduce macro NETLINK_MSG_APPEND to wrap nlmsg_append netlink: Introduce a helper function to simplify netlink functions src/util/virnetlink.c | 321 +++++++++++++++++++----------------------- src/util/virnetlink.h | 27 +--- 2 files changed, 149 insertions(+), 199 deletions(-) -- 2.25.1
NLM_F_CREATE and NLM_F_EXCL are invalid for RTM_DELLINK, so remove them. Signed-off-by: Shi Lei <shi_lei@massclouds.com> --- src/util/virnetlink.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c index ca735bb8..17e6eeb9 100644 --- a/src/util/virnetlink.c +++ b/src/util/virnetlink.c @@ -627,8 +627,7 @@ virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback) g_autoptr(virNetlinkMsg) nl_msg = NULL; g_autofree struct nlmsghdr *resp = NULL; - nl_msg = nlmsg_alloc_simple(RTM_DELLINK, - NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL); + nl_msg = nlmsg_alloc_simple(RTM_DELLINK, NLM_F_REQUEST); if (!nl_msg) { virReportOOMError(); return -1; -- 2.25.1
Move macros NETLINK_MSG_[NEST_START|NEST_END|PUT] from .h into .c; within these macros, replace 'goto' with reporting error and returning; simplify virNetlinkDumpLink and virNetlinkDelLink by using NETLINK_MSG_PUT. Signed-off-by: Shi Lei <shi_lei@massclouds.com> --- src/util/virnetlink.c | 44 +++++++++++++++++++++++++++++++++---------- src/util/virnetlink.h | 23 ---------------------- 2 files changed, 34 insertions(+), 33 deletions(-) diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c index 17e6eeb9..0b55b124 100644 --- a/src/util/virnetlink.c +++ b/src/util/virnetlink.c @@ -44,6 +44,35 @@ VIR_LOG_INIT("util.netlink"); # include <linux/veth.h> +# define NETLINK_MSG_NEST_START(msg, container, attrtype) \ +do { \ + container = nla_nest_start(msg, attrtype); \ + if (!container) { \ + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", \ + _("allocated netlink buffer is too small")); \ + return -1; \ + } \ +} while (0) + +# define NETLINK_MSG_NEST_END(msg, container) \ +do { nla_nest_end(msg, container); } while (0) + +/* + * we need to use an intermediary pointer to @data as compilers may sometimes + * complain about @data not being a pointer type: + * error: the address of 'foo' will always evaluate as 'true' [-Werror=address] + */ +# define NETLINK_MSG_PUT(msg, attrtype, datalen, data) \ +do { \ + const void *dataptr = data; \ + if (dataptr && nla_put(msg, attrtype, datalen, dataptr) < 0) { \ + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", \ + _("allocated netlink buffer is too small")); \ + return -1; \ + } \ +} while (0) + + /* State for a single netlink event handle */ struct virNetlinkEventHandle { int watch; @@ -406,10 +435,8 @@ virNetlinkDumpLink(const char *ifname, int ifindex, if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0) goto buffer_too_small; - if (ifname) { - if (nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0) - goto buffer_too_small; - } + if (ifname) + NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME, (strlen(ifname) + 1), ifname); # ifdef RTEXT_FILTER_VF /* if this filter exists in the kernel's netlink implementation, @@ -419,10 +446,8 @@ virNetlinkDumpLink(const char *ifname, int ifindex, { uint32_t ifla_ext_mask = RTEXT_FILTER_VF; - if (nla_put(nl_msg, IFLA_EXT_MASK, - sizeof(ifla_ext_mask), &ifla_ext_mask) < 0) { - goto buffer_too_small; - } + NETLINK_MSG_PUT(nl_msg, IFLA_EXT_MASK, + sizeof(ifla_ext_mask), &ifla_ext_mask); } # endif @@ -636,8 +661,7 @@ virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback) if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0) goto buffer_too_small; - if (nla_put(nl_msg, IFLA_IFNAME, strlen(ifname)+1, ifname) < 0) - goto buffer_too_small; + NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME, (strlen(ifname) + 1), ifname); if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0, NETLINK_ROUTE, 0) < 0) { diff --git a/src/util/virnetlink.h b/src/util/virnetlink.h index 7c4ed202..966d6db3 100644 --- a/src/util/virnetlink.h +++ b/src/util/virnetlink.h @@ -38,29 +38,6 @@ struct nlmsghdr; #endif /* WITH_LIBNL */ -#define NETLINK_MSG_NEST_START(msg, container, attrtype) \ -do { \ - container = nla_nest_start(msg, attrtype); \ - if (!container) \ - goto buffer_too_small; \ -} while(0) - -#define NETLINK_MSG_NEST_END(msg, container) \ -do { nla_nest_end(msg, container); } while(0) - -/* - * we need to use an intermediary pointer to @data as compilers may sometimes - * complain about @data not being a pointer type: - * error: the address of 'foo' will always evaluate as 'true' [-Werror=address] - */ -#define NETLINK_MSG_PUT(msg, attrtype, datalen, data) \ -do { \ - const void *dataptr = data; \ - if (dataptr && nla_put(msg, attrtype, datalen, dataptr) < 0) \ - goto buffer_too_small; \ -} while(0) - - int virNetlinkStartup(void); void virNetlinkShutdown(void); -- 2.25.1
Introduce a macro NETLINK_MSG_APPEND to wrap nlmsg_append and simplify code. Remove those labels 'buffer_too_small', since they are now useless. Signed-off-by: Shi Lei <shi_lei@massclouds.com> --- src/util/virnetlink.c | 42 +++++++++++++----------------------------- 1 file changed, 13 insertions(+), 29 deletions(-) diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c index 0b55b124..fdcb0dc0 100644 --- a/src/util/virnetlink.c +++ b/src/util/virnetlink.c @@ -72,6 +72,15 @@ do { \ } \ } while (0) +# define NETLINK_MSG_APPEND(msg, datalen, dataptr) \ +do { \ + if (nlmsg_append(msg, dataptr, datalen, NLMSG_ALIGNTO) < 0) { \ + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", \ + _("allocated netlink buffer is too small")); \ + return -1; \ + } \ +} while (0) + /* State for a single netlink event handle */ struct virNetlinkEventHandle { @@ -432,8 +441,7 @@ virNetlinkDumpLink(const char *ifname, int ifindex, return -1; } - if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0) - goto buffer_too_small; + NETLINK_MSG_APPEND(nl_msg, sizeof(ifinfo), &ifinfo); if (ifname) NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME, (strlen(ifname) + 1), ifname); @@ -491,11 +499,6 @@ virNetlinkDumpLink(const char *ifname, int ifindex, virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("malformed netlink response message")); return rc; - - buffer_too_small: - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("allocated netlink buffer is too small")); - return rc; } @@ -545,8 +548,7 @@ virNetlinkNewLink(const char *ifname, return -1; } - if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0) - goto buffer_too_small; + NETLINK_MSG_APPEND(nl_msg, sizeof(ifinfo), &ifinfo); NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME, (strlen(ifname) + 1), ifname); @@ -620,11 +622,6 @@ virNetlinkNewLink(const char *ifname, virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("malformed netlink response message")); return -1; - - buffer_too_small: - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("allocated netlink buffer is too small")); - return -1; } @@ -658,8 +655,7 @@ virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback) return -1; } - if (nlmsg_append(nl_msg, &ifinfo, sizeof(ifinfo), NLMSG_ALIGNTO) < 0) - goto buffer_too_small; + NETLINK_MSG_APPEND(nl_msg, sizeof(ifinfo), &ifinfo); NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME, (strlen(ifname) + 1), ifname); @@ -701,11 +697,6 @@ virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback) virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("malformed netlink response message")); return -1; - - buffer_too_small: - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("allocated netlink buffer is too small")); - return -1; } /** @@ -740,9 +731,7 @@ virNetlinkGetNeighbor(void **nlData, uint32_t src_pid, uint32_t dst_pid) return -1; } - if (nlmsg_append(nl_msg, &ndinfo, sizeof(ndinfo), NLMSG_ALIGNTO) < 0) - goto buffer_too_small; - + NETLINK_MSG_APPEND(nl_msg, sizeof(ndinfo), &ndinfo); if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, src_pid, dst_pid, NETLINK_ROUTE, 0) < 0) @@ -778,11 +767,6 @@ virNetlinkGetNeighbor(void **nlData, uint32_t src_pid, uint32_t dst_pid) virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("malformed netlink response message")); return -1; - - buffer_too_small: - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("allocated netlink buffer is too small")); - return -1; } int -- 2.25.1
Extract common code as helper function virNetlinkTalk, then simplify the functions virNetlink[DumpLink|NewLink|DelLink|GetNeighbor]. Signed-off-by: Shi Lei <shi_lei@massclouds.com> --- src/util/virnetlink.c | 232 ++++++++++++++++++------------------------ src/util/virnetlink.h | 4 +- 2 files changed, 101 insertions(+), 135 deletions(-) diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c index fdcb0dc0..650acff7 100644 --- a/src/util/virnetlink.c +++ b/src/util/virnetlink.c @@ -353,6 +353,54 @@ int virNetlinkCommand(struct nl_msg *nl_msg, return 0; } + +static int +virNetlinkTalk(const char *ifname, + virNetlinkMsg *nl_msg, + uint32_t src_pid, + uint32_t dst_pid, + struct nlmsghdr **resp, + unsigned int *resp_len, + int *error, + virNetlinkTalkFallback fallback) +{ + if (virNetlinkCommand(nl_msg, resp, resp_len, + src_pid, dst_pid, NETLINK_ROUTE, 0) < 0) + return -1; + + if (*resp_len < NLMSG_LENGTH(0) || *resp == NULL) + goto malformed_resp; + + if ((*resp)->nlmsg_type == NLMSG_ERROR) { + struct nlmsgerr *err; + + err = (struct nlmsgerr *) NLMSG_DATA(*resp); + + if ((*resp)->nlmsg_len < NLMSG_LENGTH(sizeof(*err))) + goto malformed_resp; + + if (-err->error == EOPNOTSUPP && fallback) + return fallback(ifname); + + if (err->error < 0) { + if (error) + *error = err->error; + else + virReportSystemError(-err->error, "%s", _("netlink error")); + + return -1; + } + } + + return 0; + + malformed_resp: + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed netlink response message")); + return -1; +} + + int virNetlinkDumpCommand(struct nl_msg *nl_msg, virNetlinkDumpCallback callback, @@ -396,6 +444,7 @@ virNetlinkDumpCommand(struct nl_msg *nl_msg, return 0; } + /** * virNetlinkDumpLink: * @@ -420,15 +469,14 @@ virNetlinkDumpLink(const char *ifname, int ifindex, void **nlData, struct nlattr **tb, uint32_t src_pid, uint32_t dst_pid) { - int rc = -1; - struct nlmsgerr *err; struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC, .ifi_index = ifindex }; - unsigned int recvbuflen; g_autoptr(virNetlinkMsg) nl_msg = NULL; g_autofree struct nlmsghdr *resp = NULL; + unsigned int resp_len = 0; + int error = 0; if (ifname && ifindex <= 0 && virNetDevGetIndex(ifname, &ifindex) < 0) return -1; @@ -459,46 +507,25 @@ virNetlinkDumpLink(const char *ifname, int ifindex, } # endif - if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, - src_pid, dst_pid, NETLINK_ROUTE, 0) < 0) + if (virNetlinkTalk(ifname, nl_msg, src_pid, dst_pid, + &resp, &resp_len, &error, NULL) < 0) { + virReportSystemError(error, + _("error dumping %s (%d) interface"), + ifname, ifindex); return -1; + } - if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL) - goto malformed_resp; - - switch (resp->nlmsg_type) { - case NLMSG_ERROR: - err = (struct nlmsgerr *)NLMSG_DATA(resp); - if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err))) - goto malformed_resp; - - if (err->error) { - virReportSystemError(-err->error, - _("error dumping %s (%d) interface"), - ifname, ifindex); - return -1; - } - break; - - case GENL_ID_CTRL: - case NLMSG_DONE: - rc = nlmsg_parse(resp, sizeof(struct ifinfomsg), - tb, IFLA_MAX, NULL); - if (rc < 0) - goto malformed_resp; - break; - - default: - goto malformed_resp; + if ((resp->nlmsg_type != NLMSG_ERROR && + resp->nlmsg_type != GENL_ID_CTRL && + resp->nlmsg_type != NLMSG_DONE) || + nlmsg_parse(resp, sizeof(struct ifinfomsg), tb, IFLA_MAX, NULL) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed netlink response message")); + return -1; } *nlData = g_steal_pointer(&resp); return 0; - - malformed_resp: - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("malformed netlink response message")); - return rc; } @@ -523,13 +550,12 @@ virNetlinkNewLink(const char *ifname, virNetlinkNewLinkDataPtr extra_args, int *error) { - struct nlmsgerr *err; struct nlattr *linkinfo = NULL; struct nlattr *infodata = NULL; - unsigned int buflen; struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC }; g_autoptr(virNetlinkMsg) nl_msg = NULL; g_autofree struct nlmsghdr *resp = NULL; + unsigned int resp_len = 0; *error = 0; @@ -591,37 +617,18 @@ virNetlinkNewLink(const char *ifname, } } - if (virNetlinkCommand(nl_msg, &resp, &buflen, 0, 0, NETLINK_ROUTE, 0) < 0) + if (virNetlinkTalk(ifname, nl_msg, 0, 0, + &resp, &resp_len, error, NULL) < 0) return -1; - if (buflen < NLMSG_LENGTH(0) || resp == NULL) - goto malformed_resp; - - switch (resp->nlmsg_type) { - case NLMSG_ERROR: - err = (struct nlmsgerr *)NLMSG_DATA(resp); - if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err))) - goto malformed_resp; - - if (err->error < 0) { - *error = err->error; - return -1; - } - break; - - case NLMSG_DONE: - break; - - default: - goto malformed_resp; + if (resp->nlmsg_type != NLMSG_ERROR && + resp->nlmsg_type != NLMSG_DONE) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed netlink response message")); + return -1; } return 0; - - malformed_resp: - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("malformed netlink response message")); - return -1; } @@ -641,13 +648,13 @@ virNetlinkNewLink(const char *ifname, * Returns 0 on success, -1 on fatal error. */ int -virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback) +virNetlinkDelLink(const char *ifname, virNetlinkTalkFallback fallback) { - struct nlmsgerr *err; struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC }; - unsigned int recvbuflen; g_autoptr(virNetlinkMsg) nl_msg = NULL; g_autofree struct nlmsghdr *resp = NULL; + unsigned int resp_len = 0; + int error = 0; nl_msg = nlmsg_alloc_simple(RTM_DELLINK, NLM_F_REQUEST); if (!nl_msg) { @@ -659,44 +666,22 @@ virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback) NETLINK_MSG_PUT(nl_msg, IFLA_IFNAME, (strlen(ifname) + 1), ifname); - if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0, - NETLINK_ROUTE, 0) < 0) { + if (virNetlinkTalk(ifname, nl_msg, 0, 0, + &resp, &resp_len, &error, fallback) < 0) { + virReportSystemError(error, + _("error destroying network device %s"), + ifname); return -1; } - if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL) - goto malformed_resp; - - switch (resp->nlmsg_type) { - case NLMSG_ERROR: - err = (struct nlmsgerr *)NLMSG_DATA(resp); - if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err))) - goto malformed_resp; - - if (-err->error == EOPNOTSUPP && fallback) - return fallback(ifname); - - if (err->error) { - virReportSystemError(-err->error, - _("error destroying network device %s"), - ifname); - return -1; - } - break; - - case NLMSG_DONE: - break; - - default: - goto malformed_resp; + if (resp->nlmsg_type != NLMSG_ERROR && + resp->nlmsg_type != NLMSG_DONE) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed netlink response message")); + return -1; } return 0; - - malformed_resp: - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("malformed netlink response message")); - return -1; } /** @@ -712,18 +697,18 @@ virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback) * * Get neighbor table entry from netlink. * - * Returns 0 on success, -1 on fatal error. + * Returns length of the raw data from netlink on success, -1 on fatal error. */ int virNetlinkGetNeighbor(void **nlData, uint32_t src_pid, uint32_t dst_pid) { - struct nlmsgerr *err; struct ndmsg ndinfo = { .ndm_family = AF_UNSPEC, }; - unsigned int recvbuflen; g_autoptr(virNetlinkMsg) nl_msg = NULL; g_autofree struct nlmsghdr *resp = NULL; + unsigned int resp_len = 0; + int error = 0; nl_msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_DUMP | NLM_F_REQUEST); if (!nl_msg) { @@ -733,40 +718,21 @@ virNetlinkGetNeighbor(void **nlData, uint32_t src_pid, uint32_t dst_pid) NETLINK_MSG_APPEND(nl_msg, sizeof(ndinfo), &ndinfo); - if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, - src_pid, dst_pid, NETLINK_ROUTE, 0) < 0) + if (virNetlinkTalk(NULL, nl_msg, src_pid, dst_pid, + &resp, &resp_len, &error, NULL) < 0) { + virReportSystemError(error, "%s", _("error dumping")); return -1; + } - if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL) - goto malformed_resp; - - switch (resp->nlmsg_type) { - case NLMSG_ERROR: - err = (struct nlmsgerr *)NLMSG_DATA(resp); - if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err))) - goto malformed_resp; - - if (err->error) { - virReportSystemError(-err->error, - "%s", _("error dumping")); - return -1; - } - break; - - case RTM_NEWNEIGH: - break; - - default: - goto malformed_resp; + if (resp->nlmsg_type != NLMSG_ERROR && + resp->nlmsg_type != RTM_NEWNEIGH) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed netlink response message")); + return -1; } *nlData = g_steal_pointer(&resp); - return recvbuflen; - - malformed_resp: - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("malformed netlink response message")); - return -1; + return resp_len; } int @@ -1300,7 +1266,7 @@ virNetlinkDumpLink(const char *ifname G_GNUC_UNUSED, int virNetlinkDelLink(const char *ifname G_GNUC_UNUSED, - virNetlinkDelLinkFallback fallback G_GNUC_UNUSED) + virNetlinkTalkFallback fallback G_GNUC_UNUSED) { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _(unsupported)); return -1; diff --git a/src/util/virnetlink.h b/src/util/virnetlink.h index 966d6db3..cab685fe 100644 --- a/src/util/virnetlink.h +++ b/src/util/virnetlink.h @@ -69,9 +69,9 @@ int virNetlinkNewLink(const char *ifname, virNetlinkNewLinkDataPtr data, int *error); -typedef int (*virNetlinkDelLinkFallback)(const char *ifname); +typedef int (*virNetlinkTalkFallback)(const char *ifname); -int virNetlinkDelLink(const char *ifname, virNetlinkDelLinkFallback fallback); +int virNetlinkDelLink(const char *ifname, virNetlinkTalkFallback fallback); int virNetlinkGetErrorCode(struct nlmsghdr *resp, unsigned int recvbuflen); -- 2.25.1
On 1/11/21 3:23 AM, Shi Lei wrote:
Extract common code as helper function virNetlinkTalk, then simplify the functions virNetlink[DumpLink|NewLink|DelLink|GetNeighbor].
Signed-off-by: Shi Lei <shi_lei@massclouds.com> --- src/util/virnetlink.c | 232 ++++++++++++++++++------------------------ src/util/virnetlink.h | 4 +- 2 files changed, 101 insertions(+), 135 deletions(-)
diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c index fdcb0dc0..650acff7 100644 --- a/src/util/virnetlink.c +++ b/src/util/virnetlink.c @@ -353,6 +353,54 @@ int virNetlinkCommand(struct nl_msg *nl_msg, return 0; }
+
I guess we should document that NLMSG_ERROR and err->error == 0 is a valid case and no error. How about: /** * virNetlinkTalk: * @ifname: name of the link * @nl_msg: pointer to netlink message * @src_pid: pid used for nl_pid of the local end of the netlink message * (0 == "use getpid()") * @dst_pid: pid of destination nl_pid if the kernel * is not the target of the netlink message but it is to be * sent to another process (0 if sending to the kernel) * @resp: pointer to pointer where response buffer will be allocated * @resp_len: pointer to integer holding the size of the response buffer * on return of the function * @error: pointer to store netlink error (-errno) * @fallback: pointer to an alternate function that will be called in case * netlink fails with EOPNOTSUPP (any other error will simply be * treated as an error) * * Simple wrapper around virNetlinkCommand(). The returned netlink message * is allocated at @resp. Please note that according to netlink(7) man page, * reply with type of NLMSG_ERROR and @error == 0 is an acknowledgment and * thus not an error. * * Returns: 0 on success, * -1 otherwise (error reported if @error == NULL) */
+static int +virNetlinkTalk(const char *ifname, + virNetlinkMsg *nl_msg, + uint32_t src_pid, + uint32_t dst_pid, + struct nlmsghdr **resp, + unsigned int *resp_len, + int *error, + virNetlinkTalkFallback fallback) +{ + if (virNetlinkCommand(nl_msg, resp, resp_len, + src_pid, dst_pid, NETLINK_ROUTE, 0) < 0) + return -1; + + if (*resp_len < NLMSG_LENGTH(0) || *resp == NULL) + goto malformed_resp; + + if ((*resp)->nlmsg_type == NLMSG_ERROR) { + struct nlmsgerr *err; + + err = (struct nlmsgerr *) NLMSG_DATA(*resp); + + if ((*resp)->nlmsg_len < NLMSG_LENGTH(sizeof(*err))) + goto malformed_resp; + + if (-err->error == EOPNOTSUPP && fallback) + return fallback(ifname); + + if (err->error < 0) { + if (error) + *error = err->error;
So this sets @error to a negative number. [1]
+ else + virReportSystemError(-err->error, "%s", _("netlink error")); + + return -1; + }
And here I'd put: /* According to netlink(7) man page NLMSG_ERROR packet with error * field set to 0 is an acknowledgment packet and thus not an error. */
+ } + + return 0; + + malformed_resp: + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed netlink response message")); + return -1; +} + + int virNetlinkDumpCommand(struct nl_msg *nl_msg, virNetlinkDumpCallback callback, @@ -396,6 +444,7 @@ virNetlinkDumpCommand(struct nl_msg *nl_msg, return 0; }
+ /** * virNetlinkDumpLink: * @@ -420,15 +469,14 @@ virNetlinkDumpLink(const char *ifname, int ifindex, void **nlData, struct nlattr **tb, uint32_t src_pid, uint32_t dst_pid) { - int rc = -1; - struct nlmsgerr *err; struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC, .ifi_index = ifindex }; - unsigned int recvbuflen; g_autoptr(virNetlinkMsg) nl_msg = NULL; g_autofree struct nlmsghdr *resp = NULL; + unsigned int resp_len = 0; + int error = 0;
if (ifname && ifindex <= 0 && virNetDevGetIndex(ifname, &ifindex) < 0) return -1; @@ -459,46 +507,25 @@ virNetlinkDumpLink(const char *ifname, int ifindex, } # endif
- if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, - src_pid, dst_pid, NETLINK_ROUTE, 0) < 0) + if (virNetlinkTalk(ifname, nl_msg, src_pid, dst_pid, + &resp, &resp_len, &error, NULL) < 0) { + virReportSystemError(error,
1: and here it is used as if it was positive. We need -error. And in the rest of places too. Anyway, I can fix that before pushing, so that you don't have to send another version. Do you agree if this is squashed in? diff --git c/src/util/virnetlink.c w/src/util/virnetlink.c index 650acff7d7..9bd7339054 100644 --- c/src/util/virnetlink.c +++ w/src/util/virnetlink.c @@ -354,6 +354,31 @@ int virNetlinkCommand(struct nl_msg *nl_msg, } +/** + * virNetlinkTalk: + * @ifname: name of the link + * @nl_msg: pointer to netlink message + * @src_pid: pid used for nl_pid of the local end of the netlink message + * (0 == "use getpid()") + * @dst_pid: pid of destination nl_pid if the kernel + * is not the target of the netlink message but it is to be + * sent to another process (0 if sending to the kernel) + * @resp: pointer to pointer where response buffer will be allocated + * @resp_len: pointer to integer holding the size of the response buffer + * on return of the function + * @error: pointer to store netlink error (-errno) + * @fallback: pointer to an alternate function that will be called in case + * netlink fails with EOPNOTSUPP (any other error will simply be + * treated as an error) + * + * Simple wrapper around virNetlinkCommand(). The returned netlink message + * is allocated at @resp. Please note that according to netlink(7) man page, + * reply with type of NLMSG_ERROR and @error == 0 is an acknowledgment and + * thus not an error. + * + * Returns: 0 on success, + * -1 otherwise (error reported if @error == NULL) + */ static int virNetlinkTalk(const char *ifname, virNetlinkMsg *nl_msg, @@ -390,6 +415,9 @@ virNetlinkTalk(const char *ifname, return -1; } + + /* According to netlink(7) man page NLMSG_ERROR packet with error + * field set to 0 is an acknowledgment packet and thus not an error. */ } return 0; @@ -509,7 +537,7 @@ virNetlinkDumpLink(const char *ifname, int ifindex, if (virNetlinkTalk(ifname, nl_msg, src_pid, dst_pid, &resp, &resp_len, &error, NULL) < 0) { - virReportSystemError(error, + virReportSystemError(-error, _("error dumping %s (%d) interface"), ifname, ifindex); return -1; @@ -668,7 +696,7 @@ virNetlinkDelLink(const char *ifname, virNetlinkTalkFallback fallback) if (virNetlinkTalk(ifname, nl_msg, 0, 0, &resp, &resp_len, &error, fallback) < 0) { - virReportSystemError(error, + virReportSystemError(-error, _("error destroying network device %s"), ifname); return -1; @@ -720,7 +748,7 @@ virNetlinkGetNeighbor(void **nlData, uint32_t src_pid, uint32_t dst_pid) if (virNetlinkTalk(NULL, nl_msg, src_pid, dst_pid, &resp, &resp_len, &error, NULL) < 0) { - virReportSystemError(error, "%s", _("error dumping")); + virReportSystemError(-error, "%s", _("error dumping neighbor table")); return -1; } Michal
On 2021-01-11 at 19:26, Michal Privoznik wrote:
On 1/11/21 3:23 AM, Shi Lei wrote:
Extract common code as helper function virNetlinkTalk, then simplify the functions virNetlink[DumpLink|NewLink|DelLink|GetNeighbor].
Signed-off-by: Shi Lei <shi_lei@massclouds.com> --- src/util/virnetlink.c | 232 ++++++++++++++++++------------------------ src/util/virnetlink.h | 4 +- 2 files changed, 101 insertions(+), 135 deletions(-)
diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c index fdcb0dc0..650acff7 100644 --- a/src/util/virnetlink.c +++ b/src/util/virnetlink.c @@ -353,6 +353,54 @@ int virNetlinkCommand(struct nl_msg *nl_msg, return 0; } +
I guess we should document that NLMSG_ERROR and err->error == 0 is a valid case and no error. How about:
/** * virNetlinkTalk: * @ifname: name of the link * @nl_msg: pointer to netlink message * @src_pid: pid used for nl_pid of the local end of the netlink message * (0 == "use getpid()") * @dst_pid: pid of destination nl_pid if the kernel * is not the target of the netlink message but it is to be * sent to another process (0 if sending to the kernel) * @resp: pointer to pointer where response buffer will be allocated * @resp_len: pointer to integer holding the size of the response buffer * on return of the function * @error: pointer to store netlink error (-errno) * @fallback: pointer to an alternate function that will be called in case * netlink fails with EOPNOTSUPP (any other error will simply be * treated as an error) * * Simple wrapper around virNetlinkCommand(). The returned netlink message * is allocated at @resp. Please note that according to netlink(7) man page, * reply with type of NLMSG_ERROR and @error == 0 is an acknowledgment and * thus not an error. * * Returns: 0 on success, * -1 otherwise (error reported if @error == NULL) */
+static int +virNetlinkTalk(const char *ifname, + virNetlinkMsg *nl_msg, + uint32_t src_pid, + uint32_t dst_pid, + struct nlmsghdr **resp, + unsigned int *resp_len, + int *error, + virNetlinkTalkFallback fallback) +{ + if (virNetlinkCommand(nl_msg, resp, resp_len, + src_pid, dst_pid, NETLINK_ROUTE, 0) < 0) + return -1; + + if (*resp_len < NLMSG_LENGTH(0) || *resp == NULL) + goto malformed_resp; + + if ((*resp)->nlmsg_type == NLMSG_ERROR) { + struct nlmsgerr *err; + + err = (struct nlmsgerr *) NLMSG_DATA(*resp); + + if ((*resp)->nlmsg_len < NLMSG_LENGTH(sizeof(*err))) + goto malformed_resp; + + if (-err->error == EOPNOTSUPP && fallback) + return fallback(ifname); + + if (err->error < 0) { + if (error) + *error = err->error;
So this sets @error to a negative number. [1]
+ else + virReportSystemError(-err->error, "%s", _("netlink error")); + + return -1; + }
And here I'd put:
/* According to netlink(7) man page NLMSG_ERROR packet with error * field set to 0 is an acknowledgment packet and thus not an error. */
+ } + + return 0; + + malformed_resp: + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed netlink response message")); + return -1; +} + + int virNetlinkDumpCommand(struct nl_msg *nl_msg, virNetlinkDumpCallback callback, @@ -396,6 +444,7 @@ virNetlinkDumpCommand(struct nl_msg *nl_msg, return 0; } + /** * virNetlinkDumpLink: * @@ -420,15 +469,14 @@ virNetlinkDumpLink(const char *ifname, int ifindex, void **nlData, struct nlattr **tb, uint32_t src_pid, uint32_t dst_pid) { - int rc = -1; - struct nlmsgerr *err; struct ifinfomsg ifinfo = { .ifi_family = AF_UNSPEC, .ifi_index = ifindex }; - unsigned int recvbuflen; g_autoptr(virNetlinkMsg) nl_msg = NULL; g_autofree struct nlmsghdr *resp = NULL; + unsigned int resp_len = 0; + int error = 0; if (ifname && ifindex <= 0 && virNetDevGetIndex(ifname, &ifindex) < 0) return -1; @@ -459,46 +507,25 @@ virNetlinkDumpLink(const char *ifname, int ifindex, } # endif - if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, - src_pid, dst_pid, NETLINK_ROUTE, 0) < 0) + if (virNetlinkTalk(ifname, nl_msg, src_pid, dst_pid, + &resp, &resp_len, &error, NULL) < 0) { + virReportSystemError(error,
1: and here it is used as if it was positive. We need -error. And in the rest of places too.
Anyway, I can fix that before pushing, so that you don't have to send another version. Do you agree if this is squashed in?
diff --git c/src/util/virnetlink.c w/src/util/virnetlink.c index 650acff7d7..9bd7339054 100644 --- c/src/util/virnetlink.c +++ w/src/util/virnetlink.c @@ -354,6 +354,31 @@ int virNetlinkCommand(struct nl_msg *nl_msg, }
+/** + * virNetlinkTalk: + * @ifname: name of the link + * @nl_msg: pointer to netlink message + * @src_pid: pid used for nl_pid of the local end of the netlink message + * (0 == "use getpid()") + * @dst_pid: pid of destination nl_pid if the kernel + * is not the target of the netlink message but it is to be + * sent to another process (0 if sending to the kernel) + * @resp: pointer to pointer where response buffer will be allocated + * @resp_len: pointer to integer holding the size of the response buffer + * on return of the function + * @error: pointer to store netlink error (-errno) + * @fallback: pointer to an alternate function that will be called in case + * netlink fails with EOPNOTSUPP (any other error will simply be + * treated as an error) + * + * Simple wrapper around virNetlinkCommand(). The returned netlink message + * is allocated at @resp. Please note that according to netlink(7) man page, + * reply with type of NLMSG_ERROR and @error == 0 is an acknowledgment and + * thus not an error. + * + * Returns: 0 on success, + * -1 otherwise (error reported if @error == NULL) + */ static int virNetlinkTalk(const char *ifname, virNetlinkMsg *nl_msg, @@ -390,6 +415,9 @@ virNetlinkTalk(const char *ifname,
return -1; } + + /* According to netlink(7) man page NLMSG_ERROR packet with error + * field set to 0 is an acknowledgment packet and thus not an error. */ }
return 0; @@ -509,7 +537,7 @@ virNetlinkDumpLink(const char *ifname, int ifindex,
if (virNetlinkTalk(ifname, nl_msg, src_pid, dst_pid, &resp, &resp_len, &error, NULL) < 0) { - virReportSystemError(error, + virReportSystemError(-error, _("error dumping %s (%d) interface"), ifname, ifindex); return -1; @@ -668,7 +696,7 @@ virNetlinkDelLink(const char *ifname, virNetlinkTalkFallback fallback)
if (virNetlinkTalk(ifname, nl_msg, 0, 0, &resp, &resp_len, &error, fallback) < 0) { - virReportSystemError(error, + virReportSystemError(-error, _("error destroying network device %s"), ifname); return -1; @@ -720,7 +748,7 @@ virNetlinkGetNeighbor(void **nlData, uint32_t src_pid, uint32_t dst_pid)
if (virNetlinkTalk(NULL, nl_msg, src_pid, dst_pid, &resp, &resp_len, &error, NULL) < 0) { - virReportSystemError(error, "%s", _("error dumping")); + virReportSystemError(-error, "%s", _("error dumping neighbor table")); return -1; }
Michal
I agree. Thanks! Shi Lei
On 1/12/21 2:29 AM, Shi Lei wrote:
On 2021-01-11 at 19:26, Michal Privoznik wrote:
On 1/11/21 3:23 AM, Shi Lei wrote:
Extract common code as helper function virNetlinkTalk, then simplify the functions virNetlink[DumpLink|NewLink|DelLink|GetNeighbor].
Signed-off-by: Shi Lei <shi_lei@massclouds.com> --- src/util/virnetlink.c | 232 ++++++++++++++++++------------------------ src/util/virnetlink.h | 4 +- 2 files changed, 101 insertions(+), 135 deletions(-)
Anyway, I can fix that before pushing, so that you don't have to send another version. Do you agree if this is squashed in?
I agree. Thanks!
Okay, we are currently in feature freeze preparing for release. I will push it afterwards. Michal
On 1/13/21 12:51 PM, Michal Privoznik wrote:
On 1/12/21 2:29 AM, Shi Lei wrote:
On 2021-01-11 at 19:26, Michal Privoznik wrote:
On 1/11/21 3:23 AM, Shi Lei wrote:
Extract common code as helper function virNetlinkTalk, then simplify the functions virNetlink[DumpLink|NewLink|DelLink|GetNeighbor].
Signed-off-by: Shi Lei <shi_lei@massclouds.com> --- src/util/virnetlink.c | 232 ++++++++++++++++++------------------------ src/util/virnetlink.h | 4 +- 2 files changed, 101 insertions(+), 135 deletions(-)
Anyway, I can fix that before pushing, so that you don't have to send another version. Do you agree if this is squashed in?
I agree. Thanks!
Okay, we are currently in feature freeze preparing for release. I will push it afterwards.
Pushed now. Michal
participants (2)
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Michal Privoznik -
Shi Lei