The memory mapped packet socket data structure in version 1 through 3 all contain 32-bit second values for the packet time stamps, which makes them suffer from the overflow of time_t in y2038 or y2106 (depending on whether user space interprets the value as signed or unsigned).
The implementation uses the deprecated getnstimeofday() function.
In order to get rid of that, this changes the code to use ktime_get_real_ts64() as a replacement, documenting the nature of the overflow. As long as the user applications treat the timestamps as unsigned, or only use the difference between timestamps, they are fine, and changing the timestamps to 64-bit wouldn't require a more invasive user space API change.
Note: a lot of other APIs suffer from incompatible structures when time_t gets redefined to 64-bit in 32-bit user space, but this one does not.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- net/packet/af_packet.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 737092ca9b4e..7432c6699818 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -439,17 +439,17 @@ static int __packet_get_status(struct packet_sock *po, void *frame) } }
-static __u32 tpacket_get_timestamp(struct sk_buff *skb, struct timespec *ts, +static __u32 tpacket_get_timestamp(struct sk_buff *skb, struct timespec64 *ts, unsigned int flags) { struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
if (shhwtstamps && (flags & SOF_TIMESTAMPING_RAW_HARDWARE) && - ktime_to_timespec_cond(shhwtstamps->hwtstamp, ts)) + ktime_to_timespec64_cond(shhwtstamps->hwtstamp, ts)) return TP_STATUS_TS_RAW_HARDWARE;
- if (ktime_to_timespec_cond(skb->tstamp, ts)) + if (ktime_to_timespec64_cond(skb->tstamp, ts)) return TP_STATUS_TS_SOFTWARE;
return 0; @@ -459,13 +459,20 @@ static __u32 __packet_set_timestamp(struct packet_sock *po, void *frame, struct sk_buff *skb) { union tpacket_uhdr h; - struct timespec ts; + struct timespec64 ts; __u32 ts_status;
if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp))) return 0;
h.raw = frame; + /* + * versions 1 through 3 overflow the timestamps in y2106, since they + * all store the seconds in a 32-bit unsigned integer. + * If we create a version 4, that should have a 64-bit timestamp, + * either 64-bit seconds + 32-bit nanoseconds, or just 64-bit + * nanoseconds. + */ switch (po->tp_version) { case TPACKET_V1: h.h1->tp_sec = ts.tv_sec; @@ -805,8 +812,8 @@ static void prb_close_block(struct tpacket_kbdq_core *pkc1, * It shouldn't really happen as we don't close empty * blocks. See prb_retire_rx_blk_timer_expired(). */ - struct timespec ts; - getnstimeofday(&ts); + struct timespec64 ts; + ktime_get_real_ts64(&ts); h1->ts_last_pkt.ts_sec = ts.tv_sec; h1->ts_last_pkt.ts_nsec = ts.tv_nsec; } @@ -836,7 +843,7 @@ static void prb_thaw_queue(struct tpacket_kbdq_core *pkc) static void prb_open_block(struct tpacket_kbdq_core *pkc1, struct tpacket_block_desc *pbd1) { - struct timespec ts; + struct timespec64 ts; struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
smp_rmb(); @@ -849,7 +856,7 @@ static void prb_open_block(struct tpacket_kbdq_core *pkc1, BLOCK_NUM_PKTS(pbd1) = 0; BLOCK_LEN(pbd1) = BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
- getnstimeofday(&ts); + ktime_get_real_ts64(&ts);
h1->ts_first_pkt.ts_sec = ts.tv_sec; h1->ts_first_pkt.ts_nsec = ts.tv_nsec; @@ -2184,7 +2191,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, unsigned long status = TP_STATUS_USER; unsigned short macoff, netoff, hdrlen; struct sk_buff *copy_skb = NULL; - struct timespec ts; + struct timespec64 ts; __u32 ts_status; bool is_drop_n_account = false; bool do_vnet = false; @@ -2312,7 +2319,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp))) - getnstimeofday(&ts); + ktime_get_real_ts64(&ts);
status |= ts_status;
I tried to figure out what it would take to do a version 4 mmap packet socket interface to completely avoid the y2106 overflow problem. This is what I came up with, reusing most of the v3 code, except for the parts where we access the timestamps.
For kselftest, I'm adding support for testing v4 in addition to v1-v3, but the test currently does not look at the timestamps, so it won't check that the timestamp format actually works as intended, only that I didn't break the parts that worked in the v3 selftest.
Overall, this is more of a mess than I expected, so it's probably not worth doing a v4 format just for the timestamp, but the patch can serve as a reference for anyone that needs a new format for other reasons and fixes this along with the other changes.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- Untested and rather invasive, so don't apply this part without discussion and testing --- include/uapi/linux/if_packet.h | 24 +++++- net/packet/af_packet.c | 115 ++++++++++++++++++++-------- tools/testing/selftests/net/psock_tpacket.c | 65 +++++++++------- 3 files changed, 142 insertions(+), 62 deletions(-)
diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h index 67b61d91d89b..c2cf29acdd40 100644 --- a/include/uapi/linux/if_packet.h +++ b/include/uapi/linux/if_packet.h @@ -177,8 +177,27 @@ struct tpacket3_hdr { __u8 tp_padding[8]; };
+struct tpacket4_hdr { + __u32 tp_next_offset; + __u32 tp_nsec_hi; + __u32 tp_nsec_lo; + __u32 tp_snaplen; + __u32 tp_len; + __u32 tp_status; + __u16 tp_mac; + __u16 tp_net; + /* pkt_hdr variants */ + union { + struct tpacket_hdr_variant1 hv1; + }; + __u8 tp_padding[8]; +}; + struct tpacket_bd_ts { - unsigned int ts_sec; + union { + unsigned int ts_nsec_hi; + unsigned int ts_sec; + }; union { unsigned int ts_usec; unsigned int ts_nsec; @@ -250,7 +269,8 @@ struct tpacket_block_desc { enum tpacket_versions { TPACKET_V1, TPACKET_V2, - TPACKET_V3 + TPACKET_V3, + TPACKET_V4, };
/* diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 7432c6699818..34a07e4a93a5 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -164,6 +164,7 @@ union tpacket_uhdr { struct tpacket_hdr *h1; struct tpacket2_hdr *h2; struct tpacket3_hdr *h3; + struct tpacket4_hdr *h4; void *raw; };
@@ -200,7 +201,7 @@ static void prb_retire_current_block(struct tpacket_kbdq_core *, struct packet_sock *, unsigned int status); static int prb_queue_frozen(struct tpacket_kbdq_core *); static void prb_open_block(struct tpacket_kbdq_core *, - struct tpacket_block_desc *); + struct tpacket_block_desc *, struct packet_sock *po); static void prb_retire_rx_blk_timer_expired(struct timer_list *); static void _prb_refresh_rx_retire_blk_timer(struct tpacket_kbdq_core *); static void prb_fill_rxhash(struct tpacket_kbdq_core *, struct tpacket3_hdr *); @@ -404,6 +405,7 @@ static void __packet_set_status(struct packet_sock *po, void *frame, int status) flush_dcache_page(pgv_to_page(&h.h2->tp_status)); break; case TPACKET_V3: + case TPACKET_V4: h.h3->tp_status = status; flush_dcache_page(pgv_to_page(&h.h3->tp_status)); break; @@ -430,6 +432,7 @@ static int __packet_get_status(struct packet_sock *po, void *frame) flush_dcache_page(pgv_to_page(&h.h2->tp_status)); return h.h2->tp_status; case TPACKET_V3: + case TPACKET_V4: flush_dcache_page(pgv_to_page(&h.h3->tp_status)); return h.h3->tp_status; default: @@ -439,17 +442,17 @@ static int __packet_get_status(struct packet_sock *po, void *frame) } }
-static __u32 tpacket_get_timestamp(struct sk_buff *skb, struct timespec64 *ts, +static __u32 tpacket_get_timestamp(struct sk_buff *skb, s64 *stamp, unsigned int flags) { struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
if (shhwtstamps && (flags & SOF_TIMESTAMPING_RAW_HARDWARE) && - ktime_to_timespec64_cond(shhwtstamps->hwtstamp, ts)) + (*stamp = ktime_to_ns(shhwtstamps->hwtstamp))) return TP_STATUS_TS_RAW_HARDWARE;
- if (ktime_to_timespec64_cond(skb->tstamp, ts)) + if ((*stamp = ktime_to_ns(skb->tstamp))) return TP_STATUS_TS_SOFTWARE;
return 0; @@ -460,19 +463,15 @@ static __u32 __packet_set_timestamp(struct packet_sock *po, void *frame, { union tpacket_uhdr h; struct timespec64 ts; + s64 stamp; __u32 ts_status;
- if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp))) + if (!(ts_status = tpacket_get_timestamp(skb, &stamp, po->tp_tstamp))) return 0;
h.raw = frame; - /* - * versions 1 through 3 overflow the timestamps in y2106, since they - * all store the seconds in a 32-bit unsigned integer. - * If we create a version 4, that should have a 64-bit timestamp, - * either 64-bit seconds + 32-bit nanoseconds, or just 64-bit - * nanoseconds. - */ + + ts = ns_to_timespec64(stamp); switch (po->tp_version) { case TPACKET_V1: h.h1->tp_sec = ts.tv_sec; @@ -486,6 +485,9 @@ static __u32 __packet_set_timestamp(struct packet_sock *po, void *frame, h.h3->tp_sec = ts.tv_sec; h.h3->tp_nsec = ts.tv_nsec; break; + case TPACKET_V4: + h.h4->tp_nsec_hi = upper_32_bits(stamp); + h.h4->tp_nsec_lo = lower_32_bits(stamp); default: WARN(1, "TPACKET version not supported.\n"); BUG(); @@ -633,7 +635,7 @@ static void init_prb_bdqc(struct packet_sock *po, p1->max_frame_len = p1->kblk_size - BLK_PLUS_PRIV(p1->blk_sizeof_priv); prb_init_ft_ops(p1, req_u); prb_setup_retire_blk_timer(po); - prb_open_block(p1, pbd); + prb_open_block(p1, pbd, po); }
/* Do NOT update the last_blk_num first. @@ -730,7 +732,7 @@ static void prb_retire_rx_blk_timer_expired(struct timer_list *t) * opening a block thaws the queue,restarts timer * Thawing/timer-refresh is a side effect. */ - prb_open_block(pkc, pbd); + prb_open_block(pkc, pbd, po); goto out; } } @@ -792,30 +794,43 @@ static void prb_close_block(struct tpacket_kbdq_core *pkc1, { __u32 status = TP_STATUS_USER | stat;
- struct tpacket3_hdr *last_pkt; + struct tpacket3_hdr *last_pkt_v3; + struct tpacket4_hdr *last_pkt_v4; struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1; struct sock *sk = &po->sk;
if (po->stats.stats3.tp_drops) status |= TP_STATUS_LOSING;
- last_pkt = (struct tpacket3_hdr *)pkc1->prev; - last_pkt->tp_next_offset = 0; + last_pkt_v3 = (struct tpacket3_hdr *)pkc1->prev; + last_pkt_v4 = (struct tpacket4_hdr *)pkc1->prev; + last_pkt_v3->tp_next_offset = 0;
/* Get the ts of the last pkt */ if (BLOCK_NUM_PKTS(pbd1)) { - h1->ts_last_pkt.ts_sec = last_pkt->tp_sec; - h1->ts_last_pkt.ts_nsec = last_pkt->tp_nsec; + if (po->tp_version == TPACKET_V3) { + h1->ts_last_pkt.ts_sec = last_pkt_v3->tp_sec; + h1->ts_last_pkt.ts_nsec = last_pkt_v3->tp_nsec; + } else { + h1->ts_last_pkt.ts_nsec_hi = last_pkt_v4->tp_nsec_hi; + h1->ts_last_pkt.ts_nsec = last_pkt_v4->tp_nsec_lo; + } } else { /* Ok, we tmo'd - so get the current time. * * It shouldn't really happen as we don't close empty * blocks. See prb_retire_rx_blk_timer_expired(). */ - struct timespec64 ts; - ktime_get_real_ts64(&ts); - h1->ts_last_pkt.ts_sec = ts.tv_sec; - h1->ts_last_pkt.ts_nsec = ts.tv_nsec; + if (po->tp_version == TPACKET_V3) { + struct timespec64 ts; + ktime_get_real_ts64(&ts); + h1->ts_last_pkt.ts_sec = ts.tv_sec; + h1->ts_last_pkt.ts_nsec = ts.tv_nsec; + } else { + u64 ns = ktime_get_real_ns(); + h1->ts_last_pkt.ts_nsec_hi = upper_32_bits(ns); + h1->ts_last_pkt.ts_nsec = lower_32_bits(ns); + } }
smp_wmb(); @@ -841,9 +856,8 @@ static void prb_thaw_queue(struct tpacket_kbdq_core *pkc) * */ static void prb_open_block(struct tpacket_kbdq_core *pkc1, - struct tpacket_block_desc *pbd1) + struct tpacket_block_desc *pbd1, struct packet_sock *po) { - struct timespec64 ts; struct tpacket_hdr_v1 *h1 = &pbd1->hdr.bh1;
smp_rmb(); @@ -856,10 +870,19 @@ static void prb_open_block(struct tpacket_kbdq_core *pkc1, BLOCK_NUM_PKTS(pbd1) = 0; BLOCK_LEN(pbd1) = BLK_PLUS_PRIV(pkc1->blk_sizeof_priv);
- ktime_get_real_ts64(&ts);
- h1->ts_first_pkt.ts_sec = ts.tv_sec; - h1->ts_first_pkt.ts_nsec = ts.tv_nsec; + if (po->tp_version == TPACKET_V3) { + struct timespec64 ts; + + ktime_get_real_ts64(&ts); + h1->ts_first_pkt.ts_sec = ts.tv_sec; + h1->ts_first_pkt.ts_nsec = ts.tv_nsec; + } else { + s64 ns = ktime_get_real_ns(); + + h1->ts_first_pkt.ts_nsec_hi = upper_32_bits(ns); + h1->ts_first_pkt.ts_nsec = lower_32_bits(ns); + }
pkc1->pkblk_start = (char *)pbd1; pkc1->nxt_offset = pkc1->pkblk_start + BLK_PLUS_PRIV(pkc1->blk_sizeof_priv); @@ -936,7 +959,7 @@ static void *prb_dispatch_next_block(struct tpacket_kbdq_core *pkc, * open this block and return the offset where the first packet * needs to get stored. */ - prb_open_block(pkc, pbd); + prb_open_block(pkc, pbd, po); return (void *)pkc->nxt_offset; }
@@ -1068,7 +1091,7 @@ static void *__packet_lookup_frame_in_block(struct packet_sock *po, * opening a block also thaws the queue. * Thawing is a side effect. */ - prb_open_block(pkc, pbd); + prb_open_block(pkc, pbd, po); } }
@@ -1113,6 +1136,7 @@ static void *packet_current_rx_frame(struct packet_sock *po, po->rx_ring.head, status); return curr; case TPACKET_V3: + case TPACKET_V4: return __packet_lookup_frame_in_block(po, skb, status, len); default: WARN(1, "TPACKET version not supported\n"); @@ -1171,6 +1195,7 @@ static void packet_increment_rx_head(struct packet_sock *po, case TPACKET_V2: return packet_increment_head(rb); case TPACKET_V3: + case TPACKET_V4: default: WARN(1, "TPACKET version not supported.\n"); BUG(); @@ -1279,7 +1304,7 @@ static int __packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb) return ROOM_NONE; }
- if (po->tp_version == TPACKET_V3) { + if (po->tp_version == TPACKET_V3 || po->tp_version == TPACKET_V4) { if (__tpacket_v3_has_room(po, ROOM_POW_OFF)) ret = ROOM_NORMAL; else if (__tpacket_v3_has_room(po, 0)) @@ -2192,6 +2217,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, unsigned short macoff, netoff, hdrlen; struct sk_buff *copy_skb = NULL; struct timespec64 ts; + u64 ns; __u32 ts_status; bool is_drop_n_account = false; bool do_vnet = false; @@ -2318,7 +2344,9 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
- if (!(ts_status = tpacket_get_timestamp(skb, &ts, po->tp_tstamp))) + if ((ts_status = tpacket_get_timestamp(skb, &ns, po->tp_tstamp))) + ts = ns_to_timespec64(ns); + else ktime_get_real_ts64(&ts);
status |= ts_status; @@ -2365,6 +2393,19 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, memset(h.h3->tp_padding, 0, sizeof(h.h3->tp_padding)); hdrlen = sizeof(*h.h3); break; + case TPACKET_V4: + /* identical to v3, except for the timestamp */ + h.h4->tp_status |= status; + h.h4->tp_len = skb->len; + h.h4->tp_snaplen = snaplen; + h.h4->tp_mac = macoff; + h.h4->tp_net = netoff; + ns = timespec64_to_ns(&ts); + h.h4->tp_nsec_hi = upper_32_bits(ns); + h.h4->tp_nsec_lo = lower_32_bits(ns); + memset(h.h3->tp_padding, 0, sizeof(h.h3->tp_padding)); + hdrlen = sizeof(*h.h3); + break; default: BUG(); } @@ -2570,6 +2611,7 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame, ph.raw = frame;
switch (po->tp_version) { + case TPACKET_V4: case TPACKET_V3: if (ph.h3->tp_next_offset != 0) { pr_warn_once("variable sized slot not supported"); @@ -2596,6 +2638,7 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame, off_max = po->tx_ring.frame_size - tp_len; if (po->sk.sk_type == SOCK_DGRAM) { switch (po->tp_version) { + case TPACKET_V4: case TPACKET_V3: off = ph.h3->tp_net; break; @@ -2608,6 +2651,7 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame, } } else { switch (po->tp_version) { + case TPACKET_V4: case TPACKET_V3: off = ph.h3->tp_mac; break; @@ -3658,6 +3702,7 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv len = sizeof(req_u.req); break; case TPACKET_V3: + case TPACKET_V4: default: len = sizeof(req_u.req3); break; @@ -3693,6 +3738,7 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv case TPACKET_V1: case TPACKET_V2: case TPACKET_V3: + case TPACKET_V4: break; default: return -EINVAL; @@ -3868,7 +3914,7 @@ static int packet_getsockopt(struct socket *sock, int level, int optname, memset(&po->stats, 0, sizeof(po->stats)); spin_unlock_bh(&sk->sk_receive_queue.lock);
- if (po->tp_version == TPACKET_V3) { + if (po->tp_version == TPACKET_V3 || po->tp_version == TPACKET_V4) { lv = sizeof(struct tpacket_stats_v3); st.stats3.tp_packets += st.stats3.tp_drops; data = &st.stats3; @@ -3906,6 +3952,7 @@ static int packet_getsockopt(struct socket *sock, int level, int optname, val = sizeof(struct tpacket2_hdr); break; case TPACKET_V3: + case TPACKET_V4: val = sizeof(struct tpacket3_hdr); break; default: @@ -4250,6 +4297,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u, po->tp_hdrlen = TPACKET2_HDRLEN; break; case TPACKET_V3: + case TPACKET_V4: po->tp_hdrlen = TPACKET3_HDRLEN; break; } @@ -4284,6 +4332,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u, if (unlikely(!pg_vec)) goto out; switch (po->tp_version) { + case TPACKET_V4: case TPACKET_V3: /* Block transmit is not supported yet */ if (!tx_ring) { diff --git a/tools/testing/selftests/net/psock_tpacket.c b/tools/testing/selftests/net/psock_tpacket.c index 7f6cd9fdacf3..b497632b6a70 100644 --- a/tools/testing/selftests/net/psock_tpacket.c +++ b/tools/testing/selftests/net/psock_tpacket.c @@ -3,7 +3,8 @@ * Author: Daniel Borkmann dborkman@redhat.com * Chetan Loke loke.chetan@gmail.com (TPACKET_V3 usage example) * - * A basic test of packet socket's TPACKET_V1/TPACKET_V2/TPACKET_V3 behavior. + * A basic test of packet socket's TPACKET_V1/TPACKET_V2/TPACKET_V3/TPACKET_V4 + * behavior. * * Control: * Test the setup of the TPACKET socket with different patterns that are @@ -19,6 +20,7 @@ * - TPACKET_V1: RX_RING, TX_RING * - TPACKET_V2: RX_RING, TX_RING * - TPACKET_V3: RX_RING + * - TPACKET_V4: RX_RING * * License (GPLv2): * @@ -310,12 +312,12 @@ static inline void __v2_tx_user_ready(struct tpacket2_hdr *hdr) __sync_synchronize(); }
-static inline int __v3_tx_kernel_ready(struct tpacket3_hdr *hdr) +static inline int __v3_v4_tx_kernel_ready(struct tpacket3_hdr *hdr) { return !(hdr->tp_status & (TP_STATUS_SEND_REQUEST | TP_STATUS_SENDING)); }
-static inline void __v3_tx_user_ready(struct tpacket3_hdr *hdr) +static inline void __v3_v4_tx_user_ready(struct tpacket3_hdr *hdr) { hdr->tp_status = TP_STATUS_SEND_REQUEST; __sync_synchronize(); @@ -329,7 +331,8 @@ static inline int __tx_kernel_ready(void *base, int version) case TPACKET_V2: return __v2_tx_kernel_ready(base); case TPACKET_V3: - return __v3_tx_kernel_ready(base); + case TPACKET_V4: + return __v3_v4_tx_kernel_ready(base); default: bug_on(1); return 0; @@ -346,7 +349,8 @@ static inline void __tx_user_ready(void *base, int version) __v2_tx_user_ready(base); break; case TPACKET_V3: - __v3_tx_user_ready(base); + case TPACKET_V4: + __v3_v4_tx_user_ready(base); break; } } @@ -372,6 +376,7 @@ static inline void *get_next_frame(struct ring *ring, int n) case TPACKET_V2: return ring->rd[n].iov_base; case TPACKET_V3: + case TPACKET_V4: return f0 + (n * ring->req3.tp_frame_size); default: bug_on(1); @@ -454,7 +459,8 @@ static void walk_tx(int sock, struct ring *ring) packet_len); total_bytes += ppd.v2->tp_h.tp_snaplen; break; - case TPACKET_V3: { + case TPACKET_V3: + case TPACKET_V4: { struct tpacket3_hdr *tx = next;
tx->tp_snaplen = packet_len; @@ -517,22 +523,22 @@ static void walk_v1_v2(int sock, struct ring *ring) walk_tx(sock, ring); }
-static uint64_t __v3_prev_block_seq_num = 0; +static uint64_t __v3_v4_prev_block_seq_num = 0;
-void __v3_test_block_seq_num(struct block_desc *pbd) +void __v3_v4_test_block_seq_num(struct block_desc *pbd) { - if (__v3_prev_block_seq_num + 1 != pbd->h1.seq_num) { + if (__v3_v4_prev_block_seq_num + 1 != pbd->h1.seq_num) { fprintf(stderr, "\nprev_block_seq_num:%"PRIu64", expected " "seq:%"PRIu64" != actual seq:%"PRIu64"\n", - __v3_prev_block_seq_num, __v3_prev_block_seq_num + 1, + __v3_v4_prev_block_seq_num, __v3_v4_prev_block_seq_num + 1, (uint64_t) pbd->h1.seq_num); exit(1); }
- __v3_prev_block_seq_num = pbd->h1.seq_num; + __v3_v4_prev_block_seq_num = pbd->h1.seq_num; }
-static void __v3_test_block_len(struct block_desc *pbd, uint32_t bytes, int block_num) +static void __v3_v4_test_block_len(struct block_desc *pbd, uint32_t bytes, int block_num) { if (pbd->h1.num_pkts && bytes != pbd->h1.blk_len) { fprintf(stderr, "\nblock:%u with %upackets, expected " @@ -542,23 +548,23 @@ static void __v3_test_block_len(struct block_desc *pbd, uint32_t bytes, int bloc } }
-static void __v3_test_block_header(struct block_desc *pbd, const int block_num) +static void __v3_v4_test_block_header(struct block_desc *pbd, const int block_num) { if ((pbd->h1.block_status & TP_STATUS_USER) == 0) { fprintf(stderr, "\nblock %u: not in TP_STATUS_USER\n", block_num); exit(1); }
- __v3_test_block_seq_num(pbd); + __v3_v4_test_block_seq_num(pbd); }
-static void __v3_walk_block(struct block_desc *pbd, const int block_num) +static void __v3_v4_walk_block(struct block_desc *pbd, const int block_num) { int num_pkts = pbd->h1.num_pkts, i; unsigned long bytes = 0, bytes_with_padding = ALIGN_8(sizeof(*pbd)); struct tpacket3_hdr *ppd;
- __v3_test_block_header(pbd, block_num); + __v3_v4_test_block_header(pbd, block_num);
ppd = (struct tpacket3_hdr *) ((uint8_t *) pbd + pbd->h1.offset_to_first_pkt); @@ -580,17 +586,17 @@ static void __v3_walk_block(struct block_desc *pbd, const int block_num) __sync_synchronize(); }
- __v3_test_block_len(pbd, bytes_with_padding, block_num); + __v3_v4_test_block_len(pbd, bytes_with_padding, block_num); total_bytes += bytes; }
-void __v3_flush_block(struct block_desc *pbd) +void __v3_v4_flush_block(struct block_desc *pbd) { pbd->h1.block_status = TP_STATUS_KERNEL; __sync_synchronize(); }
-static void walk_v3_rx(int sock, struct ring *ring) +static void walk_v3_v4_rx(int sock, struct ring *ring) { unsigned int block_num = 0; struct pollfd pfd; @@ -614,8 +620,8 @@ static void walk_v3_rx(int sock, struct ring *ring) while ((pbd->h1.block_status & TP_STATUS_USER) == 0) poll(&pfd, 1, 1);
- __v3_walk_block(pbd, block_num); - __v3_flush_block(pbd); + __v3_v4_walk_block(pbd, block_num); + __v3_v4_flush_block(pbd);
block_num = (block_num + 1) % ring->rd_num; } @@ -623,7 +629,7 @@ static void walk_v3_rx(int sock, struct ring *ring) pair_udp_close(udp_sock);
if (total_packets != 2 * NUM_PACKETS) { - fprintf(stderr, "walk_v3_rx: received %u out of %u pkts\n", + fprintf(stderr, "walk_v3_v4_rx: received %u out of %u pkts\n", total_packets, NUM_PACKETS); exit(1); } @@ -631,10 +637,10 @@ static void walk_v3_rx(int sock, struct ring *ring) fprintf(stderr, " %u pkts (%u bytes)", NUM_PACKETS, total_bytes >> 1); }
-static void walk_v3(int sock, struct ring *ring) +static void walk_v3_v4(int sock, struct ring *ring) { if (ring->type == PACKET_RX_RING) - walk_v3_rx(sock, ring); + walk_v3_v4_rx(sock, ring); else walk_tx(sock, ring); } @@ -655,7 +661,7 @@ static void __v1_v2_fill(struct ring *ring, unsigned int blocks) ring->flen = ring->req.tp_frame_size; }
-static void __v3_fill(struct ring *ring, unsigned int blocks, int type) +static void __v3_v4_fill(struct ring *ring, unsigned int blocks, int type) { if (type == PACKET_RX_RING) { ring->req3.tp_retire_blk_tov = 64; @@ -671,7 +677,7 @@ static void __v3_fill(struct ring *ring, unsigned int blocks, int type) ring->req3.tp_block_nr;
ring->mm_len = ring->req3.tp_block_size * ring->req3.tp_block_nr; - ring->walk = walk_v3; + ring->walk = walk_v3_v4; ring->rd_num = ring->req3.tp_block_nr; ring->flen = ring->req3.tp_block_size; } @@ -695,7 +701,8 @@ static void setup_ring(int sock, struct ring *ring, int version, int type) break;
case TPACKET_V3: - __v3_fill(ring, blocks, type); + case TPACKET_V4: + __v3_v4_fill(ring, blocks, type); ret = setsockopt(sock, SOL_PACKET, type, &ring->req3, sizeof(ring->req3)); break; @@ -804,6 +811,7 @@ static const char *tpacket_str[] = { [TPACKET_V1] = "TPACKET_V1", [TPACKET_V2] = "TPACKET_V2", [TPACKET_V3] = "TPACKET_V3", + [TPACKET_V4] = "TPACKET_V4", };
static const char *type_str[] = { @@ -854,6 +862,9 @@ int main(void) ret |= test_tpacket(TPACKET_V3, PACKET_RX_RING); ret |= test_tpacket(TPACKET_V3, PACKET_TX_RING);
+ ret |= test_tpacket(TPACKET_V4, PACKET_RX_RING); + ret |= test_tpacket(TPACKET_V4, PACKET_TX_RING); + if (ret) return 1;
Mon, Nov 27, 2017 at 05:19:25PM CET, arnd@arndb.de wrote:
I tried to figure out what it would take to do a version 4 mmap packet socket interface to completely avoid the y2106 overflow problem. This is what I came up with, reusing most of the v3 code, except for the parts where we access the timestamps.
For kselftest, I'm adding support for testing v4 in addition to v1-v3, but the test currently does not look at the timestamps, so it won't check that the timestamp format actually works as intended, only that I didn't break the parts that worked in the v3 selftest.
Overall, this is more of a mess than I expected, so it's probably not worth doing a v4 format just for the timestamp, but the patch can serve as a reference for anyone that needs a new format for other reasons and fixes this along with the other changes.
Signed-off-by: Arnd Bergmann arnd@arndb.de
[...]
@@ -250,7 +269,8 @@ struct tpacket_block_desc { enum tpacket_versions { TPACKET_V1, TPACKET_V2,
- TPACKET_V3
- TPACKET_V3,
- TPACKET_V4,
I wonder with how many versions are we going to eventually end up with :O
On Mon, Nov 27, 2017 at 11:59 AM, Jiri Pirko jiri@resnulli.us wrote:
Mon, Nov 27, 2017 at 05:19:25PM CET, arnd@arndb.de wrote:
I tried to figure out what it would take to do a version 4 mmap packet socket interface to completely avoid the y2106 overflow problem. This is what I came up with, reusing most of the v3 code, except for the parts where we access the timestamps.
For kselftest, I'm adding support for testing v4 in addition to v1-v3, but the test currently does not look at the timestamps, so it won't check that the timestamp format actually works as intended, only that I didn't break the parts that worked in the v3 selftest.
Overall, this is more of a mess than I expected, so it's probably not worth doing a v4 format just for the timestamp, but the patch can serve as a reference for anyone that needs a new format for other reasons and fixes this along with the other changes.
Signed-off-by: Arnd Bergmann arnd@arndb.de
[...]
@@ -250,7 +269,8 @@ struct tpacket_block_desc { enum tpacket_versions { TPACKET_V1, TPACKET_V2,
TPACKET_V3
TPACKET_V3,TPACKET_V4,I wonder with how many versions are we going to eventually end up with :O
There already is an effort to come up with a new AF_PACKET V4 [1]. We should make sure that any new interface does not have the Y2038/Y2106 issue. But, if a new version is being developed and that subsumes all existing use cases, then there probably is no need for another version that is a very small diff to V3.
If adding support for existing applications is useful, another approach would be to add a new socket option that changes the semantics for the two u32 fields in each of V1, V2 and V3 to hold nsec. Add a single check after filling in those structs whether the option is set and, if so, overwrite the two fields.
On Mon, Nov 27, 2017 at 9:35 PM, Willem de Bruijn willemdebruijn.kernel@gmail.com wrote:
On Mon, Nov 27, 2017 at 11:59 AM, Jiri Pirko jiri@resnulli.us wrote:
Mon, Nov 27, 2017 at 05:19:25PM CET, arnd@arndb.de wrote:
I tried to figure out what it would take to do a version 4 mmap packet socket interface to completely avoid the y2106 overflow problem. This is what I came up with, reusing most of the v3 code, except for the parts where we access the timestamps.
For kselftest, I'm adding support for testing v4 in addition to v1-v3, but the test currently does not look at the timestamps, so it won't check that the timestamp format actually works as intended, only that I didn't break the parts that worked in the v3 selftest.
Overall, this is more of a mess than I expected, so it's probably not worth doing a v4 format just for the timestamp, but the patch can serve as a reference for anyone that needs a new format for other reasons and fixes this along with the other changes.
Signed-off-by: Arnd Bergmann arnd@arndb.de
[...]
@@ -250,7 +269,8 @@ struct tpacket_block_desc { enum tpacket_versions { TPACKET_V1, TPACKET_V2,
TPACKET_V3
TPACKET_V3,TPACKET_V4,I wonder with how many versions are we going to eventually end up with :O
There already is an effort to come up with a new AF_PACKET V4 [1]. We should make sure that any new interface does not have the Y2038/Y2106 issue. But, if a new version is being developed and that subsumes all existing use cases, then there probably is no need for another version that is a very small diff to V3.
Ah, perfect, that's good timing. Adding Björn to Cc here.
If adding support for existing applications is useful, another approach would be to add a new socket option that changes the semantics for the two u32 fields in each of V1, V2 and V3 to hold nsec. Add a single check after filling in those structs whether the option is set and, if so, overwrite the two fields.
I don't think that's necessary. As long as the V4 capabilities are a superset of V1-V3, we should be able to just require all users to move to V4 (or later) in the next 89 years, and make sure that they use unsigned seconds if they care about 2038.
Arnd
2017-11-27 21:51 GMT+01:00 Arnd Bergmann arnd@arndb.de: [...]
There already is an effort to come up with a new AF_PACKET V4 [1]. We should make sure that any new interface does not have the Y2038/Y2106 issue. But, if a new version is being developed and that subsumes all existing use cases, then there probably is no need for another version that is a very small diff to V3.
Ah, perfect, that's good timing. Adding Björn to Cc here.
Unfortunately, for the Y2038/Y2106 cases, we'll be (as a result of netdevconf discussions) moving the AF_PACKET V4 implementation to a separate, new, address/packet family.
If adding support for existing applications is useful, another approach would be to add a new socket option that changes the semantics for the two u32 fields in each of V1, V2 and V3 to hold nsec. Add a single check after filling in those structs whether the option is set and, if so, overwrite the two fields.
I don't think that's necessary. As long as the V4 capabilities are a superset of V1-V3, we should be able to just require all users to move to V4 (or later) in the next 89 years, and make sure that they use unsigned seconds if they care about 2038.
Given that V4 wont be around for AF_PACKET -- at least not in the shape of our patches -- Willem's suggestion is probably a good way forward.
Arnd
On Tue, Nov 28, 2017 at 8:04 AM, Björn Töpel bjorn.topel@gmail.com wrote:
2017-11-27 21:51 GMT+01:00 Arnd Bergmann arnd@arndb.de: [...]
There already is an effort to come up with a new AF_PACKET V4 [1]. We should make sure that any new interface does not have the Y2038/Y2106 issue. But, if a new version is being developed and that subsumes all existing use cases, then there probably is no need for another version that is a very small diff to V3.
Ah, perfect, that's good timing. Adding Björn to Cc here.
Unfortunately, for the Y2038/Y2106 cases, we'll be (as a result of netdevconf discussions) moving the AF_PACKET V4 implementation to a separate, new, address/packet family.
Ok, I see.
If adding support for existing applications is useful, another approach would be to add a new socket option that changes the semantics for the two u32 fields in each of V1, V2 and V3 to hold nsec. Add a single check after filling in those structs whether the option is set and, if so, overwrite the two fields.
I don't think that's necessary. As long as the V4 capabilities are a superset of V1-V3, we should be able to just require all users to move to V4 (or later) in the next 89 years, and make sure that they use unsigned seconds if they care about 2038.
Given that V4 wont be around for AF_PACKET -- at least not in the shape of our patches -- Willem's suggestion is probably a good way forward.
That leaves one question: should we do that now, or wait until some other reason for a V4 comes up? I don't mind creating another patch for this, just want to get a feeling of whether the API clutter is worth it when we have a way out that works until y2106 (at which point we run into other problems as well).
Arnd
On Tue, Nov 28, 2017 at 3:46 AM, Arnd Bergmann arnd@arndb.de wrote:
On Tue, Nov 28, 2017 at 8:04 AM, Björn Töpel bjorn.topel@gmail.com wrote:
2017-11-27 21:51 GMT+01:00 Arnd Bergmann arnd@arndb.de: [...]
There already is an effort to come up with a new AF_PACKET V4 [1]. We should make sure that any new interface does not have the Y2038/Y2106 issue. But, if a new version is being developed and that subsumes all existing use cases, then there probably is no need for another version that is a very small diff to V3.
Ah, perfect, that's good timing. Adding Björn to Cc here.
Unfortunately, for the Y2038/Y2106 cases, we'll be (as a result of netdevconf discussions) moving the AF_PACKET V4 implementation to a separate, new, address/packet family.
Ok, I see.
Does it matter whether the replacement is a new version or a new packet family?
If adding support for existing applications is useful, another approach would be to add a new socket option that changes the semantics for the two u32 fields in each of V1, V2 and V3 to hold nsec. Add a single check after filling in those structs whether the option is set and, if so, overwrite the two fields.
I don't think that's necessary. As long as the V4 capabilities are a superset of V1-V3, we should be able to just require all users to move to V4 (or later) in the next 89 years, and make sure that they use unsigned seconds if they care about 2038.
Given that V4 wont be around for AF_PACKET -- at least not in the shape of our patches -- Willem's suggestion is probably a good way forward.
That leaves one question: should we do that now, or wait until some other reason for a V4 comes up? I don't mind creating another patch for this, just want to get a feeling of whether the API clutter is worth it when we have a way out that works until y2106 (at which point we run into other problems as well).
I don't expect that we'll have another packet version independent from the work that Björn is doing. The choice to implement using a new packet family is given by the complexity of the existing code, especially the various locking mechanisms.
From that point of view, and if we want to offer a Y2106 proof
AF_PACKET independent from the above, no reason to wait.
On Tue, Nov 28, 2017 at 3:08 PM, Willem de Bruijn willemdebruijn.kernel@gmail.com wrote:
On Tue, Nov 28, 2017 at 3:46 AM, Arnd Bergmann arnd@arndb.de wrote:
On Tue, Nov 28, 2017 at 8:04 AM, Björn Töpel bjorn.topel@gmail.com wrote:
2017-11-27 21:51 GMT+01:00 Arnd Bergmann arnd@arndb.de: [...]
There already is an effort to come up with a new AF_PACKET V4 [1]. We should make sure that any new interface does not have the Y2038/Y2106 issue. But, if a new version is being developed and that subsumes all existing use cases, then there probably is no need for another version that is a very small diff to V3.
Ah, perfect, that's good timing. Adding Björn to Cc here.
Unfortunately, for the Y2038/Y2106 cases, we'll be (as a result of netdevconf discussions) moving the AF_PACKET V4 implementation to a separate, new, address/packet family.
Ok, I see.
Does it matter whether the replacement is a new version or a new packet family?
It depends on whether the new packet family provides a superset of the AF_PACKET features or not. If we can expect that all users of AF_PACKET can migrate to the replacement over time, then doing it there is sufficient, otherwise adding 64-bit timestamps into AF_PACKET may be a better way to upgrade existing users.
If adding support for existing applications is useful, another approach would be to add a new socket option that changes the semantics for the two u32 fields in each of V1, V2 and V3 to hold nsec. Add a single check after filling in those structs whether the option is set and, if so, overwrite the two fields.
I don't think that's necessary. As long as the V4 capabilities are a superset of V1-V3, we should be able to just require all users to move to V4 (or later) in the next 89 years, and make sure that they use unsigned seconds if they care about 2038.
Given that V4 wont be around for AF_PACKET -- at least not in the shape of our patches -- Willem's suggestion is probably a good way forward.
That leaves one question: should we do that now, or wait until some other reason for a V4 comes up? I don't mind creating another patch for this, just want to get a feeling of whether the API clutter is worth it when we have a way out that works until y2106 (at which point we run into other problems as well).
I don't expect that we'll have another packet version independent from the work that Björn is doing. The choice to implement using a new packet family is given by the complexity of the existing code, especially the various locking mechanisms.
Ok.
From that point of view, and if we want to offer a Y2106 proof AF_PACKET independent from the above, no reason to wait.
Agreed.
Arnd
-
Arnd Bergmann -
Björn Töpel -
Jiri Pirko -
Willem de Bruijn